Aaron的博客

好巧妙，双指针法，找到顶峰，左边开始数到最大，再从右边开始数到最大。class Solution(object): def trap(self, height): """ :type height: List[int] :rtype: int """ if len(height)<=2:

原方法参见博文：http://www.cnblogs.com/grandyang/p/6927921.htmlhere is an m by n grid with a ball. Given the start coordinate (i,j) of the ball, you can move the ball to adjacent cell or cross the grid bo

You are given n pairs of numbers. In every pair, the first number is always smaller than the second number.Now, we define a pair (c, d) can follow another pair (a, b) if and only if b . Chain

Implement wildcard pattern matching with support for '?' and '*'.'?' Matches any single character.'*' Matches any sequence of characters (including the empty sequence).The matching should cov

Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999.因为罗马计数对于每一位数字计数规则都是一样的，所以我们可以给个、十、百、千位都打一张罗马计数表，然后把输入的数字按位逐次表示出来，就OKAY了，非常简单机械的方法。但是由

A frog is crossing a river. The river is divided into x units and at each unit there may or may not exist a stone. The frog can jump on a stone, but it must not jump into the water.Given a list of

Given a string, find the length of the longest substring without repeating characters.Examples:Given "abcabcbb", the answer is "abc", which the length is 3.Given "bbbbb", the answer is "

Given a set of candidate numbers (C) (without duplicates) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.The same repeated number may be chosen

Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring.For "(()", the longest valid parentheses substring is "()",

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.合并两个有序链表，只允许通过两个链表相互插接的方式自己写怎么也写不出，后来才知道用递归做，既简洁又高效率。

Given two binary trees and imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are not.You need to merge them into a new binary tr

题目:There are N children standing in a line. Each child is assigned a rating value.You are giving candies to these children subjected to the following requirements:Each child must have at

Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.无限超时。。。最后用这个O（n2）复杂度class Sol

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, ai) and (i, 0). Fin

Given a collection of numbers that might contain duplicates, return all possible unique permutations.For example,[1,1,2] have the following unique permutations:[ [1,1,2], [1,2,1], [2,1,1