CNoodle

[LeetCode] 993. Cousins in Binary Tree

Given the root of a binary tree with unique values and the values of two different nodes of the tree x and y, return true if the nodes corresponding to the values x and y in the tree are cousins, or f

2020-05-08

#leetcode #java #tree #bfs #dfs

[LeetCode] 443. String Compression

Given an array of characters chars, compress it using the following algorithm:Begin with an empty string s. For each group of consecutive repeating characters in chars:If the group’s length is 1, appe

2020-05-08

#leetcode #two pointer #java #string #simulation

[LeetCode] 130. Surrounded Regions

You are given an m x n matrix board containing letters ‘X’ and ‘O’, capture regions that are surrounded: Connect: A cell is connected to adjacent cells horizontally or vertically.Region: To form a reg

2020-05-02

#leetcode #array #java #bfs #dfs #matrix

[LeetCode] 1095. Find in Mountain Array

(This problem is an interactive problem.) You may recall that an array arr is a mountain array if and only if: arr.length >= 3There exists some i with 0 < i < arr.length - 1 such that:ar

2020-04-29

#leetcode #array #java #binary search

[LeetCode] 704. Binary Search

Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1. You

2020-04-29

#leetcode #java #javascript #binary search

[LeetCode] 221. Maximal Square

Given an m x n binary matrix filled with 0’s and 1’s, find the largest square containing only 1’s and return its area. Example 1: Input: matrix = [[“1”,”0”,”1”,”0”,”0”],[“1”,”0”,”1”,”1”,”1”],[“1”

2020-04-28

#leetcode #java #dynamic programming #matrix

[LeetCode] 621. Task Scheduler

You are given an array of CPU tasks, each represented by letters A to Z, and a cooling time, n. Each cycle or interval allows the completion of one task. Tasks can be completed in any order, but there

2020-04-26

#leetcode #hashmap #java #greedy #heap

[LeetCode] 18. 4Sum

Given an array nums of n integers, return an array of all the unique quadruplets [nums[a], nums[b], nums[c], nums[d]] such that:0 <= a, b, c, d < na, b, c, and d are distinct.nums[a] + nums

2020-04-26

#leetcode #array #two pointer #java #javascript #two sum

[LeetCode] 380. Insert Delete GetRandom O(1)

Design a data structure that supports all following operations in average O(1) time. insert(val): Inserts an item val to the set if not already present.remove(val): Removes an item val from the set if

2020-04-24

#leetcode #array #hashmap #java #math #design #random

[LeetCode] 80. Remove Duplicates from Sorted Array II

Given an integer array nums sorted in non-decreasing order, remove some duplicates in-place such that each unique element appears at most twice. The relative order of the elements should be kept the s

2020-04-22

#leetcode #array #two pointer #java #javascript