455-AssignCookies
Problem Assume you are an awesome parent and want to give your children some cookies. But, you should give each child at most one cookie. Each child i has a greed factor gi, which is the minimum size
Read More70. Climbing Stairs
70. Climbing Stairs
Problem You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top? Note: Given n will be a po
Read More226. Invert Binary Tree
226. Invert Binary Tree
Problem Invert a binary tree. 4 / \ 2 7 / \ / \ 1 3 6 9 Output: 4 / \ 7 2 / \ / \ 9 6 3 1 Thought Process Can solve this question recursively. if the root is None, return None else, revert root&rs
Read More104. Maximum Depth of Binary Tree
104. Maximum Depth of Binary Tree
Problem Given a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. Note: A leaf is a node with no c
Read More20. Valid Parentheses
20. Valid Parentheses
Problem Given a string containing just the characters ‘(’, ‘)’, ‘{’, ‘}’, ‘[’ and ‘]’, determine if the input string is valid. A
Read More206. Reverse Linked List
206. Reverse Linked List
Problem Reverse a singly linked list. Example: Input: 1->2->3->4->5->NULL Output: NULL<-1<-2<-3<-4<-5 Follow up: A linked list can be reversed either iteratively or rec
Read More447. Number of Boomerangs
447. Number of Boomerangs
Problem Given n points in the plane that are all pairwise distinct, a “boomerang” is a tuple of points (i, j, k) such that the distance between i and j equals the distance between i and k
Read More454. 4Sum II
454. 4Sum II
Problem Given four lists A, B, C, D of integer values, compute how many tuples (i, j, k, l) there are such that A[i] + B[j] + C[k] + D[l] is zero. To make problem a bit easier, all A, B, C, D have sam
Read More1. Two Sum
1. Two Sum
Problem Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and you may not use t
Read More350. Intersection of Two Arrays II
350. Intersection of Two Arrays II
Problem Given two arrays, write a function to compute their intersection. Example 1: Input: nums1 = [1,2,2,1], nums2 = [2,2] Output: [2,2] Example 2: Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4] Out
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