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import java.util.*;class Solution_TimeLimit { //使用两层for循环会导致超时。此时应该想到用其他方法。 public boolean containsNearbyDuplicate(int[] nums, int k) { for(int i=0;i<nums.length-1;i++) { for(int j=

DecriptionGiven an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), ..., (an, bn) which makes sum of min(ai, bi) for all i from 1

DescriptionThe Hamming distance between two integers is the number of positions at which the corresponding bits are different.Given two integers x and y, calculate the Hamming distance.

205. Isomorphic Strings问题描述：Given two strings s and t, determine if they are isomorphic.Two strings are isomorphic if the characters in s can be replaced to gett.All occurrences of a cha

299. Bulls and Cows问题描述：You are playing the following Bulls and Cows game with your friend: You write down a number and ask your friend to guess what the number is. Each time your friend mak

205. Isomorphic Strings问题描述：Given two strings s and t, determine if they are isomorphic.Two strings are isomorphic if the characters in s can be replaced to gett.All occurrences of a cha

101. Symmetric Tree 问题描述：Total Accepted: 145790Total Submissions: 397211Difficulty: EasyContributors: Admin Given a binary tree, check whether it is a mirror of itsel

19. Remove Nth Node From End of List问题描述：Given a linked list, remove the nth node from the end of list and return its head.For example, Given linked list: 1->2->3->4->5, and n = 2. A

题目：Given a non-empty string check if it can be constructed by taking a substring of it and appending multiple copies of the substring together. You may assume the given string consists of lowercas

一、【二叉树是神马？】准载文章段落：关于树和二叉树的基本概念总结1.什么是（自由）树？树首先是无向图的一种，并且此无向图要满足下面两个特性：1）连通，即任何两对顶点之间都有路径相连。2）无回路，简单地说就是没有成环。2.什么是森林？当满足树特性2）而不满足1）时称为森林。可以简单地理解为，什么不满足连通性，所以森林中可含有多个（自由）树。3.树的特性

/*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]]*/import java.util

/*杨辉三角：输入行数（从第零行开始），输出杨辉三角相应行数。例如：输入3，输出1,3,3,1注意规律：num=num*(rowIndex-i)/(i+1); List list=new ArrayList(); long num=1; for(int i=0;i<=rowIndex;i++) { list.add((int)num); num=num*(row

class Solution_TimeLimit{ int maxprofit=0; if(prices.length==0) return 0; for(int i=0;i<prices.length-1;i++) { for(int j=i+1;j<prices.length;j++) { if(maxprofit<prices[j]-prices[i])

import java.util.*;public class Solution { public int majorityElement(int[] nums) { HashMap hm=new HashMap(); int key=0; if(nums.length==1) return nums[0]; for(int i=0;i<nums

import java.util.*;class Solution_TimeLimit { public void rotate(int[] nums, int k) { for(int i=0;i<k;i++) { int temp=nums[nums.length-1]; for(int j=nums.length-1;j>0;j--) { nums

class Solution { public boolean containsDuplicate(int[] nums) { HashMap hm=new HashMap(); for(int i=0;i<nums.length;i++) { if(!(hm.containsKey(nums[i]))) hm.put(nums[i],0); e

二刷了，一刷做完了easy部分，做了一点medium，再刷一遍做好总结。EasyNOTITLESOLUTION461Hamming Distance题解561Array Partition I题解