# Category Leetcode Solutions

## [Solved] There is an m x n matrix that is initialized to all 0’s. There is also a 2D array indices where each indices[i] = [ri, ci] represents a 0-indexed location to perform some increment operations on the matrix.

Question There is an m x n matrix that is initialized to all 0‘s. There is also a 2D array indices where each indices[i] = [ri, ci] represents a 0-indexed location to perform some increment operations on the matrix. For each location indices[i], do both of the following: Increment all the cells on row ri.…

## [Solved] Given a callable function f(x, y) with a hidden formula and a value z, reverse engineer the formula and return all positive integer pairs x and y where f(x,y) == z. You may return the pairs in any order.

Question Given a callable function f(x, y) with a hidden formula and a value z, reverse engineer the formula and return all positive integer pairs x and y where f(x,y) == z. You may return the pairs in any order. While the exact formula is hidden, the function is monotonically…

## [Solved] Balanced strings are those that have an equal quantity of ‘L’ and ‘R’ characters. Given a balanced string s, split it into some number of substrings such that: Each substring is balanced.

Question Balanced strings are those that have an equal quantity of ‘L’ and ‘R’ characters. Given a balanced string s, split it into some number of substrings such that: Each substring is balanced. Return the maximum number of balanced strings you can obtain. Example 1: Input: s = “RLRRLLRLRL” Output: 4…

## [Solved] Given an array of integers arr, return true if the number of occurrences of each value in the array is unique, or false otherwise.

Question Given an array of integers arr, return true if the number of occurrences of each value in the array is unique, or false otherwise. Example 1: Input: arr = [1,2,2,1,1,3] Output: true Explanation: The value 1 has 3 occurrences, 2 has 2 and 3 has 1.…

## [Solved] Given a string text, you want to use the characters of text to form as many instances of the word “balloon” as possible. You can use each character in text at most once. Return the maximum number of instances that can be formed.

Question Given a string text, you want to use the characters of text to form as many instances of the word “balloon” as possible. You can use each character in text at most once. Return the maximum number of instances that can be formed. Example 1: Input:…

## [Solved] Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on. Return the smallest level x such that the sum of all the values of nodes at level x is maximal.

Question Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on. Return the smallest level x such that the sum of all the values of nodes at level x is maximal. Example 1: Input: root = [1,7,0,7,-8,null,null]…

## [Solved] You are given an array of strings words and a string chars. A string is good if it can be formed by characters from chars (each character can only be used once). Return the sum of lengths of all good strings in words.

Question You are given an array of strings words and a string chars. A string is good if it can be formed by characters from chars (each character can only be used once). Return the sum of lengths of all good strings in words. Example 1:…

## [Solved] Given two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0.

Question Given two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0. A subsequence of a string is a new string generated from the original string with some characters (can be none) deleted without changing the relative order of…

## [Solved] Given a valid (IPv4) IP address, return a defanged version of that IP address. A defanged IP address replaces every period “.” with “[.]”.

Question Given a valid (IPv4) IP address, return a defanged version of that IP address. A defanged IP address replaces every period “.” with “[.]”. Example 1: Input: address = “1.1.1.1” Output: “1[.]1[.]1[.]1” Example 2: Input: address = “255.100.50.0” Output: “255[.]100[.]50[.]0” Constraints: The given address is a valid IPv4…

## [Solved] Given two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0.

Question Given two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0. A subsequence of a string is a new string generated from the original string with some characters (can be none) deleted without changing the relative order of…