[LeetCode] 49. Group Anagrams
Given an array of strings strs, group the anagrams together. You can return the answer in any order. An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typ
[LeetCode] 451. Sort Characters By Frequency
Given a string s, sort it in decreasing order based on the frequency of characters, and return the sorted string. Example 1:Input: s = “tree”Output: “eert”Explanation: ‘e’ appears twice while ‘r’
[LeetCode] 138. Copy List with Random Pointer
A linked list of length n is given such that each node contains an additional random pointer, which could point to any node in the list, or null. Construct a deep copy of the list. The deep copy shoul
[LeetCode] 9. Palindrome Number
Given an integer x, return true if x is a palindrome, and false otherwise. Example 1:Input: x = 121Output: trueExplanation: 121 reads as 121 from left to right and from right to left. Example 2:I
[LeetCode] 589. N-ary Tree Preorder Traversal
Given the root of an n-ary tree, return the preorder traversal of its nodes’ values. Nary-Tree input serialization is represented in their level order traversal. Each group of children is separated by
[LeetCode] 506. Relative Ranks
You are given an integer array score of size n, where score[i] is the score of the ith athlete in a competition. All the scores are guaranteed to be unique. The athletes are placed based on their scor
[LeetCode] 513. Find Bottom Left Tree Value
Given the root of a binary tree, return the leftmost value in the last row of the tree. Example 1:Input: root = [2,1,3]Output: 1 Example 2:Input: root = [1,2,3,4,null,5,6,null,null,7]Output:
[LeetCode] 113. Path Sum II
Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values in the path equals targetSum. Each path should be returned as a list of the nod