题目： Given a binary tree, return the bottom-up level order traversal of its nodes’ values. (ie,…

题目描述 Given a positive integer, return its corresponding column title as appear in an Excel sheet. For example:…

Maximal Square Given a 2D binary matrix filled with 0’s and 1’s, find the largest square containin…

78. Subsets 题目 Given a set of distinct integers, nums, return all possible subsets (the power set). Note: The …

  A zero-indexed array A consisting of N different integers is given. The array contains all integers in …

  Give a string s, count the number of non-empty (contiguous) substrings that have the same number o…

  We have two integer sequences A and B of the same non-zero length. We are allowed t…

  Given a binary tree, find the largest subtree which is a Binary Search Tree (BST), where largest means …

  Given two non-negative numbers num1 and num2 represented as string, return the sum of num1 and num2. No…

  A sorted list A contains 1, plus some number of primes.  Then, for every p < q in the…

Zigzag Iterator Given two 1d vectors, implement an iterator to return their elements alternately. For example,…

1. 题目 Given n, how many structurally unique BST’s (binary search trees) that store values 1…n? For…