LeetCode Solutions - Page 5

1608. Special Array With X Elements Greater Than or Equal X

Junior

Description:

You are given an array nums of non-negative integers. nums is considered special if there exists a number x such that there are exactly x numbers in nums that are greater than or equal to x.

Notice that x does not have to be an element in nums.

Return x _if the array is special, otherwise, return _-1. It can be proven that if nums is special, the value for x is unique.

Example 1:

Input: nums = [3,5]
Output: 2
Explanation: There are 2 values (3 and 5) that are greater than or equal to 2.

Example 2:

Input: nums = [0,0]
Output: -1
Explanation: No numbers fit the criteria for x.
If x = 0, there should be 0 numbers >= x, but there are 2.
If x = 1, there should be 1 number >= x, but there are 0.
If x = 2, there should be 2 numbers >= x, but there are 0.
x cannot be greater since there are only 2 numbers in nums.

Example 3:

Input: nums = [0,4,3,0,4]
Output: 3
Explanation: There are 3 values that are greater than or equal to 3.

Constraints:

1 <= nums.length <= 100
0 <= nums[i] <= 1000

Code:

// PHP solution for this challenge is currently being updated.

1652. Defuse the Bomb

Junior

Description:

You have a bomb to defuse, and your time is running out! Your informer will provide you with a circular array code of length of n and a key k.

To decrypt the code, you must replace every number. All the numbers are replaced simultaneously.

If k > 0, replace the i^th number with the sum of the next k numbers.
If k < 0, replace the i^th number with the sum of the previous -k numbers.
If k == 0, replace the i^th number with 0.

As code is circular, the next element of code[n-1] is code[0], and the previous element of code[0] is code[n-1].

Given the circular array code and an integer key k, return the decrypted code to defuse the bomb!

Example 1:

Input: code = [5,7,1,4], k = 3
Output: [12,10,16,13]
Explanation: Each number is replaced by the sum of the next 3 numbers. The decrypted code is [7+1+4, 1+4+5, 4+5+7, 5+7+1]. Notice that the numbers wrap around.

Example 2:

Input: code = [1,2,3,4], k = 0
Output: [0,0,0,0]
Explanation: When k is zero, the numbers are replaced by 0.

Example 3:

Input: code = [2,4,9,3], k = -2
Output: [12,5,6,13]
Explanation: The decrypted code is [3+9, 2+3, 4+2, 9+4]. Notice that the numbers wrap around again. If k is negative, the sum is of the previous numbers.

Constraints:

n == code.length
1 <= n <= 100
1 <= code[i] <= 100
-(n - 1) <= k <= n - 1

Code:

// PHP solution for this challenge is currently being updated.

1662. Check If Two String Arrays are Equivalent

Junior

Description:

Given two string arrays word1 and word2, return* true if the two arrays represent the same string, and false otherwise.*

A string is represented by an array if the array elements concatenated in order forms the string.

Example 1:

Input: word1 = ["ab", "c"], word2 = ["a", "bc"]
Output: true
Explanation:
word1 represents string "ab" + "c" -> "abc"
word2 represents string "a" + "bc" -> "abc"
The strings are the same, so return true.

Example 2:

Input: word1 = ["a", "cb"], word2 = ["ab", "c"]
Output: false

Example 3:

Input: word1  = ["abc", "d", "defg"], word2 = ["abcddefg"]
Output: true

Constraints:

1 <= word1.length, word2.length <= 10^3
1 <= word1[i].length, word2[i].length <= 10^3
1 <= sum(word1[i].length), sum(word2[i].length) <= 10^3
word1[i] and word2[i] consist of lowercase letters.

Code:

// PHP solution for this challenge is currently being updated.

1678. Goal Parser Interpretation

Junior

Description:

You own a Goal Parser that can interpret a string command. The command consists of an alphabet of "G", "()" and/or "(al)" in some order. The Goal Parser will interpret "G" as the string "G", "()" as the string "o", and "(al)" as the string "al". The interpreted strings are then concatenated in the original order.

Given the string command, return _the Goal Parser's interpretation of _command.

Example 1:

Input: command = "G()(al)"
Output: "Goal"
Explanation: The Goal Parser interprets the command as follows:
G -> G
() -> o
(al) -> al
The final concatenated result is "Goal".

Example 2:

Input: command = "G()()()()(al)"
Output: "Gooooal"

Example 3:

Input: command = "(al)G(al)()()G"
Output: "alGalooG"

Constraints:

1 <= command.length <= 100
command consists of "G", "()", and/or "(al)" in some order.

Code:

// PHP solution for this challenge is currently being updated.

1684. Count the Number of Consistent Strings

Junior

Description:

You are given a string allowed consisting of distinct characters and an array of strings words. A string is **consistent **if all characters in the string appear in the string allowed.

Return* the number of consistent strings in the array *words.

Example 1:

Input: allowed = "ab", words = ["ad","bd","aaab","baa","badab"]
Output: 2
Explanation: Strings "aaab" and "baa" are consistent since they only contain characters &#39;a&#39; and &#39;b&#39;.

Example 2:

Input: allowed = "abc", words = ["a","b","c","ab","ac","bc","abc"]
Output: 7
Explanation: All strings are consistent.

Example 3:

Input: allowed = "cad", words = ["cc","acd","b","ba","bac","bad","ac","d"]
Output: 4
Explanation: Strings "cc", "acd", "ac", and "d" are consistent.

Constraints:

1 <= words.length <= 10^4
1 <= allowed.length <=^ 26
1 <= words[i].length <= 10
The characters in allowed are distinct.
words[i] and allowed contain only lowercase English letters.

Code:

// PHP solution for this challenge is currently being updated.

1710. Maximum Units on a Truck

Junior

Description:

You are assigned to put some amount of boxes onto one truck. You are given a 2D array boxTypes, where boxTypes[i] = [numberOfBoxes~i, numberOfUnitsPerBox~i]:

numberOfBoxes~i is the number of boxes of type i.
numberOfUnitsPerBox~i~ is the number of units in each box of the type i.

You are also given an integer truckSize, which is the maximum number of boxes that can be put on the truck. You can choose any boxes to put on the truck as long as the number of boxes does not exceed truckSize.

Return the maximum total number of units that can be put on the truck.

Example 1:

Input: boxTypes = [[1,3],[2,2],[3,1]], truckSize = 4
Output: 8
Explanation: There are:
- 1 box of the first type that contains 3 units.
- 2 boxes of the second type that contain 2 units each.
- 3 boxes of the third type that contain 1 unit each.
You can take all the boxes of the first and second types, and one box of the third type.
The total number of units will be = (1 * 3) + (2 * 2) + (1 * 1) = 8.

Example 2:

Input: boxTypes = [[5,10],[2,5],[4,7],[3,9]], truckSize = 10
Output: 91

Constraints:

1 <= boxTypes.length <= 1000
1 <= numberOfBoxes~i, numberOfUnitsPerBox~i <= 1000
1 <= truckSize <= 10^6

Code:

// PHP solution for this challenge is currently being updated.

1716. Calculate Money in Leetcode Bank

Junior

Description:

Hercy wants to save money for his first car. He puts money in the Leetcode bank every day.

He starts by putting in $1 on Monday, the first day. Every day from Tuesday to Sunday, he will put in $1 more than the day before. On every subsequent Monday, he will put in $1 more than the previous Monday.

Given n, return the total amount of money he will have in the Leetcode bank at the end of the n^th day.

Example 1:

Input: n = 4
Output: 10
Explanation: After the 4^th day, the total is 1 + 2 + 3 + 4 = 10.

Example 2:

Input: n = 10
Output: 37
Explanation: After the 10^th day, the total is (1 + 2 + 3 + 4 + 5 + 6 + 7) + (2 + 3 + 4) = 37. Notice that on the 2^nd Monday, Hercy only puts in $2.

Example 3:

Input: n = 20
Output: 96
Explanation: After the 20^th day, the total is (1 + 2 + 3 + 4 + 5 + 6 + 7) + (2 + 3 + 4 + 5 + 6 + 7 + 8) + (3 + 4 + 5 + 6 + 7 + 8) = 96.

Constraints:

1 <= n <= 1000

Code:

// PHP solution for this challenge is currently being updated.

1796. Second Largest Digit in a String

Junior

Description:

Given an alphanumeric string s, return the second largest numerical digit that appears in s, or -1 if it does not exist.

An alphanumeric** **string is a string consisting of lowercase English letters and digits.

Example 1:

Input: s = "dfa12321afd"
Output: 2
Explanation: The digits that appear in s are [1, 2, 3]. The second largest digit is 2.

Example 2:

Input: s = "abc1111"
Output: -1
Explanation: The digits that appear in s are [1]. There is no second largest digit.

Constraints:

1 <= s.length <= 500
s consists of only lowercase English letters and digits.

Code:

// PHP solution for this challenge is currently being updated.

1832. Check if the Sentence Is Pangram

Junior

Description:

A pangram is a sentence where every letter of the English alphabet appears at least once.

Given a string sentence containing only lowercase English letters, return* true if sentence is a pangram, or false otherwise.*

Example 1:

Input: sentence = "thequickbrownfoxjumpsoverthelazydog"
Output: true
Explanation: sentence contains at least one of every letter of the English alphabet.

Example 2:

Input: sentence = "leetcode"
Output: false

Constraints:

1 <= sentence.length <= 1000
sentence consists of lowercase English letters.

Code:

// PHP solution for this challenge is currently being updated.

1863. Sum of All Subset XOR Totals

Junior

Description:

The XOR total of an array is defined as the bitwise XOR of** all its elements**, or 0 if the array is** empty**.

For example, the XOR total of the array [2,5,6] is 2 XOR 5 XOR 6 = 1.

Given an array nums, return _the sum of all XOR totals for every subset of _nums.

Note: Subsets with the same elements should be counted multiple times.

An array a is a subset of an array b if a can be obtained from b by deleting some (possibly zero) elements of b.

Example 1:

Input: nums = [1,3]
Output: 6
Explanation: The 4 subsets of [1,3] are:
- The empty subset has an XOR total of 0.
- [1] has an XOR total of 1.
- [3] has an XOR total of 3.
- [1,3] has an XOR total of 1 XOR 3 = 2.
0 + 1 + 3 + 2 = 6

Example 2:

Input: nums = [5,1,6]
Output: 28
Explanation: The 8 subsets of [5,1,6] are:
- The empty subset has an XOR total of 0.
- [5] has an XOR total of 5.
- [1] has an XOR total of 1.
- [6] has an XOR total of 6.
- [5,1] has an XOR total of 5 XOR 1 = 4.
- [5,6] has an XOR total of 5 XOR 6 = 3.
- [1,6] has an XOR total of 1 XOR 6 = 7.
- [5,1,6] has an XOR total of 5 XOR 1 XOR 6 = 2.
0 + 5 + 1 + 6 + 4 + 3 + 7 + 2 = 28

Example 3:

Input: nums = [3,4,5,6,7,8]
Output: 480
Explanation: The sum of all XOR totals for every subset is 480.

Constraints:

1 <= nums.length <= 12
1 <= nums[i] <= 20

Code:

// PHP solution for this challenge is currently being updated.

1971. Find if Path Exists in Graph

Junior

Description:

There is a bi-directional graph with n vertices, where each vertex is labeled from 0 to n - 1 (inclusive). The edges in the graph are represented as a 2D integer array edges, where each edges[i] = [u~i, v~i] denotes a bi-directional edge between vertex u~i and vertex v~i. Every vertex pair is connected by at most one edge, and no vertex has an edge to itself.

You want to determine if there is a valid path that exists from vertex source to vertex destination.

Given edges and the integers n, source, and destination, return true_ if there is a valid path from source to destination, or false otherwise**._

Example 1:

Input: n = 3, edges = [[0,1],[1,2],[2,0]], source = 0, destination = 2
Output: true
Explanation: There are two paths from vertex 0 to vertex 2:
- 0 &rarr; 1 &rarr; 2
- 0 &rarr; 2

Example 2:

Input: n = 6, edges = [[0,1],[0,2],[3,5],[5,4],[4,3]], source = 0, destination = 5
Output: false
Explanation: There is no path from vertex 0 to vertex 5.

Constraints:

1 <= n <= 2 * 10^5
0 <= edges.length <= 2 * 10^5
edges[i].length == 2
0 <= u~i, v~i <= n - 1
u~i != v~i
0 <= source, destination <= n - 1
There are no duplicate edges.
There are no self edges.

Code:

// PHP solution for this challenge is currently being updated.

1978. Employees Whose Manager Left the Company

Junior

Description:

Table: Employees

+-------------+----------+
| Column Name | Type     |
+-------------+----------+
| employee_id | int      |
| name        | varchar  |
| manager_id  | int      |
| salary      | int      |
+-------------+----------+
In SQL, employee_id is the primary key for this table.
This table contains information about the employees, their salary, and the ID of their manager. Some employees do not have a manager (manager_id is null).

Find the IDs of the employees whose salary is strictly less than $30000 and whose manager left the company. When a manager leaves the company, their information is deleted from the Employees table, but the reports still have their manager_id set to the manager that left.

Return the result table ordered by employee_id.

The result format is in the following example.

Example 1:

Input:
Employees table:
+-------------+-----------+------------+--------+
| employee_id | name      | manager_id | salary |
+-------------+-----------+------------+--------+
| 3           | Mila      | 9          | 60301  |
| 12          | Antonella | null       | 31000  |
| 13          | Emery     | null       | 67084  |
| 1           | Kalel     | 11         | 21241  |
| 9           | Mikaela   | null       | 50937  |
| 11          | Joziah    | 6          | 28485  |
+-------------+-----------+------------+--------+
Output:
+-------------+
| employee_id |
+-------------+
| 11          |
+-------------+

Explanation:
The employees with a salary less than $30000 are 1 (Kalel) and 11 (Joziah).
Kalel&#39;s manager is employee 11, who is still in the company (Joziah).
Joziah&#39;s manager is employee 6, who left the company because there is no row for employee 6 as it was deleted.

Code:

// PHP solution for this challenge is currently being updated.

2006. Count Number of Pairs With Absolute Difference K

Junior

Description:

Given an integer array nums and an integer k, return the number of pairs (i, j) where i < j such that |nums[i] - nums[j]| == k.

The value of |x| is defined as:

x if x >= 0.
-x if x < 0.

Example 1:

Input: nums = [1,2,2,1], k = 1
Output: 4
Explanation: The pairs with an absolute difference of 1 are:
- [_1_,_2_,2,1]
- [_1_,2,_2_,1]
- [1,_2_,2,_1_]
- [1,2,_2_,_1_]

Example 2:

Input: nums = [1,3], k = 3
Output: 0
Explanation: There are no pairs with an absolute difference of 3.

Example 3:

Input: nums = [3,2,1,5,4], k = 2
Output: 3
<b>Explanation:</b> The pairs with an absolute difference of 2 are:
- [_3_,2,_1_,5,4]
- [_3_,2,1,_5_,4]
- [3,_2_,1,5,_4_]

Constraints:

1 <= nums.length <= 200
1 <= nums[i] <= 100
1 <= k <= 99

Code:

// PHP solution for this challenge is currently being updated.

2169. Count Operations to Obtain Zero

Junior

Description:

You are given two non-negative integers num1 and num2.

In one operation, if num1 >= num2, you must subtract num2 from num1, otherwise subtract num1 from num2.

For example, if num1 = 5 and num2 = 4, subtract num2 from num1, thus obtaining num1 = 1 and num2 = 4. However, if num1 = 4 and num2 = 5, after one operation, num1 = 4 and num2 = 1.

Return the number of operations required to make either num1 = 0 or num2 = 0.

Example 1:

Input: num1 = 2, num2 = 3
Output: 3
Explanation:
- Operation 1: num1 = 2, num2 = 3. Since num1 < num2, we subtract num1 from num2 and get num1 = 2, num2 = 3 - 2 = 1.
- Operation 2: num1 = 2, num2 = 1. Since num1 > num2, we subtract num2 from num1.
- Operation 3: num1 = 1, num2 = 1. Since num1 == num2, we subtract num2 from num1.
Now num1 = 0 and num2 = 1. Since num1 == 0, we do not need to perform any further operations.
So the total number of operations required is 3.

Example 2:

Input: num1 = 10, num2 = 10
Output: 1
Explanation:
- Operation 1: num1 = 10, num2 = 10. Since num1 == num2, we subtract num2 from num1 and get num1 = 10 - 10 = 0.
Now num1 = 0 and num2 = 10. Since num1 == 0, we are done.
So the total number of operations required is 1.

Constraints:

0 <= num1, num2 <= 10^5

Code:

// PHP solution for this challenge is currently being updated.

2200. Find All K-Distant Indices in an Array

Junior

Description:

You are given a 0-indexed integer array nums and two integers key and k. A k-distant index is an index i of nums for which there exists at least one index j such that |i - j| <= k and nums[j] == key.

Return *a list of all k-distant indices sorted in increasing order*.

Example 1:

Input: nums = [3,4,9,1,3,9,5], key = 9, k = 1
Output: [1,2,3,4,5,6]
Explanation: Here, `nums[2] == key` and `nums[5] == key.
- For index 0, |0 - 2| > k and |0 - 5| > k, so there is no j` where `|0 - j| <= k` and `nums[j] == key. Thus, 0 is not a k-distant index.
- For index 1, |1 - 2| <= k and nums[2] == key, so 1 is a k-distant index.
- For index 2, |2 - 2| <= k and nums[2] == key, so 2 is a k-distant index.
- For index 3, |3 - 2| <= k and nums[2] == key, so 3 is a k-distant index.
- For index 4, |4 - 5| <= k and nums[5] == key, so 4 is a k-distant index.
- For index 5, |5 - 5| <= k and nums[5] == key, so 5 is a k-distant index.
- For index 6, |6 - 5| <= k and nums[5] == key, so 6 is a k-distant index.
`Thus, we return [1,2,3,4,5,6] which is sorted in increasing order.

Example 2:

Input: nums = [2,2,2,2,2], key = 2, k = 2
Output: [0,1,2,3,4]
Explanation: For all indices i in nums, there exists some index j such that |i - j| <= k and nums[j] == key, so every index is a k-distant index.
Hence, we return [0,1,2,3,4].

Constraints:

1 <= nums.length <= 1000
1 <= nums[i] <= 1000
key is an integer from the array nums.
1 <= k <= nums.length

Code:

// PHP solution for this challenge is currently being updated.

2269. Find the K-Beauty of a Number

Junior

Description:

The k-beauty of an integer num is defined as the number of substrings of num when it is read as a string that meet the following conditions:

It has a length of k.
It is a divisor of num.

Given integers num and k, return _the k-beauty of _num.

Note:

Leading zeros are allowed.
0 is not a divisor of any value.

A substring is a contiguous sequence of characters in a string.

Example 1:

Input: num = 240, k = 2
Output: 2
Explanation: The following are the substrings of num of length k:
- "24" from "_24_0": 24 is a divisor of 240.
- "40" from "2_40_": 40 is a divisor of 240.
Therefore, the k-beauty is 2.

Example 2:

Input: num = 430043, k = 2
Output: 2
Explanation: The following are the substrings of num of length k:
- "43" from "_43_0043": 43 is a divisor of 430043.
- "30" from "4_30_043": 30 is not a divisor of 430043.
- "00" from "43_00_43": 0 is not a divisor of 430043.
- "04" from "430_04_3": 4 is not a divisor of 430043.
- "43" from "4300_43_": 43 is a divisor of 430043.
Therefore, the k-beauty is 2.

Constraints:

1 <= num <= 10^9
1 <= k <= num.length (taking num as a string)

Code:

// PHP solution for this challenge is currently being updated.

2309. Greatest English Letter in Upper and Lower Case

Junior

Description:

Given a string of English letters s, return the **greatest **English letter which occurs as both a lowercase and uppercase letter in s. The returned letter should be in uppercase. If no such letter exists, return an empty string.

An English letter b is greater than another letter a if b appears after a in the English alphabet.

Example 1:

Input: s = "l_Ee_TcOd_E_"
Output: "E"
Explanation:
The letter &#39;E&#39; is the only letter to appear in both lower and upper case.

Example 2:

Input: s = "a_rR_AzFif"
Output: "R"
Explanation:
The letter &#39;R&#39; is the greatest letter to appear in both lower and upper case.
Note that &#39;A&#39; and &#39;F&#39; also appear in both lower and upper case, but &#39;R&#39; is greater than &#39;F&#39; or &#39;A&#39;.

Example 3:

Input: s = "AbCdEfGhIjK"
Output: ""
Explanation:
There is no letter that appears in both lower and upper case.

Constraints:

1 <= s.length <= 1000
s consists of lowercase and uppercase English letters.

Code:

// PHP solution for this challenge is currently being updated.

2367. Number of Arithmetic Triplets

Junior

Description:

You are given a 0-indexed, strictly increasing integer array nums and a positive integer diff. A triplet (i, j, k) is an arithmetic triplet if the following conditions are met:

i < j < k,
nums[j] - nums[i] == diff, and
nums[k] - nums[j] == diff.

Return the number of unique arithmetic triplets.

Example 1:

Input: nums = [0,1,4,6,7,10], diff = 3
Output: 2
Explanation:
(1, 2, 4) is an arithmetic triplet because both 7 - 4 == 3 and 4 - 1 == 3.
(2, 4, 5) is an arithmetic triplet because both 10 - 7 == 3 and 7 - 4 == 3.

Example 2:

Input: nums = [4,5,6,7,8,9], diff = 2
Output: 2
Explanation:
(0, 2, 4) is an arithmetic triplet because both 8 - 6 == 2 and 6 - 4 == 2.
(1, 3, 5) is an arithmetic triplet because both 9 - 7 == 2 and 7 - 5 == 2.

Constraints:

3 <= nums.length <= 200
0 <= nums[i] <= 200
1 <= diff <= 50
nums is strictly increasing.

Code:

// PHP solution for this challenge is currently being updated.

2389. Longest Subsequence With Limited Sum

Junior

Description:

You are given an integer array nums of length n, and an integer array queries of length m.

Return _an array answer of length m where answer[i] is the maximum size of a subsequence that you can take from nums such that the sum of its elements is less than or equal to _queries[i].

A subsequence is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.

Example 1:

Input: nums = [4,5,2,1], queries = [3,10,21]
Output: [2,3,4]
Explanation: We answer the queries as follows:
- The subsequence [2,1] has a sum less than or equal to 3. It can be proven that 2 is the maximum size of such a subsequence, so answer[0] = 2.
- The subsequence [4,5,1] has a sum less than or equal to 10. It can be proven that 3 is the maximum size of such a subsequence, so answer[1] = 3.
- The subsequence [4,5,2,1] has a sum less than or equal to 21. It can be proven that 4 is the maximum size of such a subsequence, so answer[2] = 4.

Example 2:

Input: nums = [2,3,4,5], queries = [1]
Output: [0]
Explanation: The empty subsequence is the only subsequence that has a sum less than or equal to 1, so answer[0] = 0.

Constraints:

n == nums.length
m == queries.length
1 <= n, m <= 1000
1 <= nums[i], queries[i] <= 10^6

Code:

// PHP solution for this challenge is currently being updated.

2427. Number of Common Factors

Junior

Description:

Given two positive integers a and b, return _the number of common factors of a and _b.

An integer x is a common factor of a and b if x divides both a and b.

Example 1:

Input: a = 12, b = 6
Output: 4
Explanation: The common factors of 12 and 6 are 1, 2, 3, 6.

Example 2:

Input: a = 25, b = 30
Output: 2
Explanation: The common factors of 25 and 30 are 1, 5.

Constraints:

1 <= a, b <= 1000

Code:

// PHP solution for this challenge is currently being updated.

2437. Number of Valid Clock Times

Junior

Description:

You are given a string of length 5 called time, representing the current time on a digital clock in the format "hh:mm". The earliest possible time is "00:00" and the latest possible time is "23:59".

In the string time, the digits represented by the ? symbol are unknown, and must be replaced with a digit from 0 to 9.

Return* an integer *answer_, the number of valid clock times that can be created by replacing every ? with a digit from 0 to _9.

Example 1:

Input: time = "?5:00"
Output: 2
Explanation: We can replace the ? with either a 0 or 1, producing "05:00" or "15:00". Note that we cannot replace it with a 2, since the time "25:00" is invalid. In total, we have two choices.

Example 2:

Input: time = "0?:0?"
Output: 100
Explanation: Each ? can be replaced by any digit from 0 to 9, so we have 100 total choices.

Example 3:

Input: time = "??:??"
Output: 1440
Explanation: There are 24 possible choices for the hours, and 60 possible choices for the minutes. In total, we have 24 * 60 = 1440 choices.

Constraints:

time is a valid string of length 5 in the format "hh:mm".
"00" <= hh <= "23"
"00" <= mm <= "59"
Some of the digits might be replaced with '?' and need to be replaced with digits from 0 to 9.

Code:

// PHP solution for this challenge is currently being updated.

2475. Number of Unequal Triplets in Array

Junior

Description:

You are given a 0-indexed array of positive integers nums. Find the number of triplets (i, j, k) that meet the following conditions:

0 <= i < j < k < nums.length
nums[i], nums[j], and nums[k] are pairwise distinct.
- In other words, nums[i] != nums[j], nums[i] != nums[k], and nums[j] != nums[k].

Return the number of triplets that meet the conditions.

Example 1:

Input: nums = [4,4,2,4,3]
Output: 3
Explanation: The following triplets meet the conditions:
- (0, 2, 4) because 4 != 2 != 3
- (1, 2, 4) because 4 != 2 != 3
- (2, 3, 4) because 2 != 4 != 3
Since there are 3 triplets, we return 3.
Note that (2, 0, 4) is not a valid triplet because 2 > 0.

Example 2:

Input: nums = [1,1,1,1,1]
Output: 0
Explanation: No triplets meet the conditions so we return 0.

Constraints:

3 <= nums.length <= 100
1 <= nums[i] <= 1000

Code:

// PHP solution for this challenge is currently being updated.

2490. Circular Sentence

Junior

Description:

A sentence is a list of words that are separated by a** single** space with no leading or trailing spaces.

For example, "Hello World", "HELLO", "hello world hello world" are all sentences.

Words consist of only uppercase and lowercase English letters. Uppercase and lowercase English letters are considered different.

A sentence is **circular **if:

The last character of each word in the sentence is equal to the first character of its next word.
The last character of the last word is equal to the first character of the first word.

For example, "leetcode exercises sound delightful", "eetcode", "leetcode eats soul" are all circular sentences. However, "Leetcode is cool", "happy Leetcode", "Leetcode" and "I like Leetcode" are not circular sentences.

Given a string sentence, return true_ if it is circular_. Otherwise, return false.

Example 1:

Input: sentence = "leetcode exercises sound delightful"
Output: true
Explanation: The words in sentence are ["leetcode", "exercises", "sound", "delightful"].
- leetcod_e_&#39;s last character is equal to _e_xercises&#39;s first character.
- exercise_s_&#39;s last character is equal to _s_ound&#39;s first character.
- soun_d_&#39;s last character is equal to _d_elightful&#39;s first character.
- delightfu_l_&#39;s last character is equal to _l_eetcode&#39;s first character.
The sentence is circular.

Example 2:

Input: sentence = "eetcode"
Output: true
Explanation: The words in sentence are ["eetcode"].
- eetcod_e_&#39;s last character is equal to _e_etcode&#39;s first character.
The sentence is circular.

Example 3:

Input: sentence = "Leetcode is cool"
Output: false
Explanation: The words in sentence are ["Leetcode", "is", "cool"].
- Leetcod_e_&#39;s last character is not equal to _i_s&#39;s first character.
The sentence is not circular.

Constraints:

1 <= sentence.length <= 500
sentence consist of only lowercase and uppercase English letters and spaces.
The words in sentence are separated by a single space.
There are no leading or trailing spaces.

Code:

// PHP solution for this challenge is currently being updated.

2529. Maximum Count of Positive Integer and Negative Integer

Junior

Description:

Given an array nums sorted in non-decreasing order, return the maximum between the number of positive integers and the number of negative integers.

In other words, if the number of positive integers in nums is pos and the number of negative integers is neg, then return the maximum of pos and neg.

Note that 0 is neither positive nor negative.

Example 1:

Input: nums = [-2,-1,-1,1,2,3]
Output: 3
Explanation: There are 3 positive integers and 3 negative integers. The maximum count among them is 3.

Example 2:

Input: nums = [-3,-2,-1,0,0,1,2]
Output: 3
Explanation: There are 2 positive integers and 3 negative integers. The maximum count among them is 3.

Example 3:

Input: nums = [5,20,66,1314]
Output: 4
Explanation: There are 4 positive integers and 0 negative integers. The maximum count among them is 4.

Constraints:

1 <= nums.length <= 2000
-2000 <= nums[i] <= 2000
nums is sorted in a non-decreasing order.

Follow up: Can you solve the problem in O(log(n)) time complexity?

Code:

// PHP solution for this challenge is currently being updated.

2578. Split With Minimum Sum

Junior

Description:

Given a positive integer num, split it into two non-negative integers num1 and num2 such that:

The concatenation of num1 and num2 is a permutation of num.
- In other words, the sum of the number of occurrences of each digit in num1 and num2 is equal to the number of occurrences of that digit in num.
num1 and num2 can contain leading zeros.

Return the minimum possible sum of num1 and num2.

Notes:

It is guaranteed that num does not contain any leading zeros.
The order of occurrence of the digits in num1 and num2 may differ from the order of occurrence of num.

Example 1:

Input: num = 4325
Output: 59
Explanation: We can split 4325 so that `num1` is 24 and `num2` is 35, giving a sum of 59. We can prove that 59 is indeed the minimal possible sum.

Example 2:

Input: num = 687
Output: 75
Explanation: We can split 687 so that `num1` is 68 and `num2` is 7, which would give an optimal sum of 75.

Constraints:

10 <= num <= 10^9

Code:

// PHP solution for this challenge is currently being updated.

2582. Pass the Pillow

Junior

Description:

There are n people standing in a line labeled from 1 to n. The first person in the line is holding a pillow initially. Every second, the person holding the pillow passes it to the next person standing in the line. Once the pillow reaches the end of the line, the direction changes, and people continue passing the pillow in the opposite direction.

For example, once the pillow reaches the n^th person they pass it to the n - 1^th person, then to the n - 2^th person and so on.

Given the two positive integers n and time, return the index of the person holding the pillow after time seconds.

Example 1:

Input: n = 4, time = 5
Output: 2
Explanation: People pass the pillow in the following way: 1 -> 2 -> 3 -> 4 -> 3 -> 2.
After five seconds, the 2^nd person is holding the pillow.

Example 2:

Input: n = 3, time = 2
Output: 3
Explanation: People pass the pillow in the following way: 1 -> 2 -> 3.
After two seconds, the 3^r^d person is holding the pillow.

Constraints:

2 <= n <= 1000
1 <= time <= 1000

Note: This question is the same as 3178: Find the Child Who Has the Ball After K Seconds.

Code:

// PHP solution for this challenge is currently being updated.