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摘要： 1. 问题描述 Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). Note: Bonus points if you could solve it both r 阅读全文

摘要： 1. 问题描述 You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint sto 阅读全文

摘要： 1. 问题描述 Given a binary tree, determine if it is height-balanced.For this problem, a height-balanced binary tree is defined as a binary tree in which t 阅读全文

摘要： 1. 问题描述 Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST.According to the definition of LCA on Wi 阅读全文

摘要： 1. 问题描述 Write a program to check whether a given number is an ugly number.Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. 阅读全文

摘要： 1. 问题描述 Write an algorithm to determine if a number is "happy".A happy number is a number defined by the following process: Starting with any positive 阅读全文

摘要： 1. 问题描述 Given a linked list, determine if it has a cycle in it.Follow up:Can you solve it without using extra space?Tags: Linked List Two PointersSimi 阅读全文

摘要： 1. 问题描述 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 阅读全文

摘要： 1. 问题描述 Implement strStr().Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.Tags：Two Pointers 阅读全文

摘要： 1. 问题描述 Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the give 阅读全文