zgljl2012

问题描述 Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. * push(x) -- Push element x onto stack. * pop() -- Removes the element on top of

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? 代码 class Solution { public: bool hasCycle(ListNode *head) { ListNode* p

问题描述 Given an array of integers, every element appears twice except for one. Find that single one. Note: Your algorithm should have a linear runtime complexity. Could you implement it without using extra

问题描述 Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i,

问题描述 Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example, "A man, a plan, a canal: Panama" is a palindrome. "race a car" is

问题描述 Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to complete at most one transaction (ie,

问题描述 Given an index k, return the kth row of the Pascal's triangle. For example, given k = 3, Return [1,3,3,1]. Note: Could you optimize your algorithm to use only O(

问题描述 Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5, Return [ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1] ] 分析 设f(

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 given sum. For example: Given

问题描述 Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. 二叉树最短路径问题。 问题分析

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 the depth of the two subtrees of every

问题描述 Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root). For example: Given binary tree [3,