Problem You are given an integer array nums. In one move, you can pick an index i where 0 <= i < nums.length and increment nums[i] by 1. Return the minimum number of moves to make every value in nums unique. The test cases are generated so that the answer fits in a 32-bit integer. Examples Example 1: Input: nums = [1,2,2] Output: 1 Explanation: After 1 move, the array could be [1, 2, 3]. ...
Problem Given the root of an n-ary tree, return the postorder traversal of its nodes’ values. Nary-Tree input serialization is represented in their level order traversal. Each group of children is separated by the null value (See examples) Examples Example 1: graph TD 1 --- A[3] & B[2] & C[4] A --- 5 & 6 (have to use A, B, C in mermaid to make the ordering of nodes better) ...
Problem On a 2D plane, we place n stones at some integer coordinate points. Each coordinate point may have at most one stone. A stone can be removed if it shares either the same row or the same column as another stone that has not been removed. Given an array stones of length n where stones[i] = [xi, yi] represents the location of the ith stone, return the largest possible number of stones that can be removed. ...
Problem Given two integer arrays nums1 and nums2, return an array of their intersection. Each element in the result must be unique and you may return the result in any order. Examples Example 1: Input: nums1 = [1, 2, 2, 1], nums2 = [2, 2] Output: [2] ...
Problem Given an array nums with n objects colored red, white, or blue, sort them in-place so that objects of the same color are adjacent, with the colors in the order red, white, and blue. We will use the integers 0, 1, and 2 to represent the color red, white, and blue, respectively. You must solve this problem without using the library’s sort function. By the way this is Dutch National Flag - 🇳🇱. ...
Problem Given an integer array nums where the elements are sorted in ascending order, convert it to a height-balanced binary search tree. Examples Example 1: Input: nums = [1, 2, 3, 4, 5, 6] Output: [3,2,5,1,null,4,6] Explanation: [4,2,5,1,3,null,6] is also accepted. ...
Problem Alice and Bob continue their games with piles of stones. There are a number of piles arranged in a row, and each pile has a positive integer number of stones piles[i]. The objective of the game is to end with the most stones. Alice and Bob take turns, with Alice starting first. Initially, M = 1. On each player’s turn, that player can take all the stones in the first X remaining piles, where 1 <= X <= 2M. Then, we set M = max(M, X). ...
Problem Given two strings s and t, return true if s is a subsequence of t, or false otherwise. OR Given two strings str1 and str2, find if str1 is a subsequence of str2. Subarrays vs Subsequences vs Subsets Definition Follow up Expected time complexity is linear. Suppose there are lots of incoming s, say s1, s2, ..., sk where k >= 109, and you want to check one by one to see if t has its subsequence. In this scenario, how would you change your code? Examples Example 1: ...
Problem You are given two m x n binary matrices grid1 and grid2 containing only 0’s (representing water) and 1’s (representing land). An island is a group of 1’s connected 4-directionally (horizontal or vertical). Any cells outside of the grid are considered water cells. An island in grid2 is considered a sub-island if there is an island in grid1 that contains all the cells that make up this island in grid2. ...
Problem You are given an m x n binary grid grid where 1 represents land and 0 represents water. An island is a maximal 4-directionally (horizontal or vertical) connected group of 1’s. The grid is said to be connected if we have exactly one island, otherwise is said disconnected. In one day, we are allowed to change any single land cell (1) into a water cell (0). ...