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给定一个长度为n的整数数组nums，数组中所有的数字都在0∼n−1的范围内。数组中某些数字是重复的，但不知道有几个数字重复了，也不知道每个数字重复了几次。请找出数组中任意一个重复的数字。注意：如果某些数字不在0∼n−1的范围内，或数组中不包含重复数字，则返回 -1；样例给定 nums = [2, 3, 5, 4, 3, 2, 6, 7]。 返回 2 或 3。...

packagecom.ytx.array;/** 题目： sort-colors *      *     描述： Given an array with n objects colored red, white or blue, sort them so that objects of the same color *                  are adjacen

packagecom.ytx.array;/** 题目：remove-duplicates-from-sorted-array-ii * *     描述： Follow up for "Remove Duplicates": *             What if duplicates are allowed at most twice?              

packagecom.ytx.array;/** 题目：remove-element * *     描述： Given an array and a value, remove all instances of that value in place and return the new length.                    The order of elem

packagecom.ytx.array;/** 题目： container-with-most-water * *     描述： Given n non-negative integers a1 , a2 , ..., an , where each represents a point at *                  coordinate (i,ai

packagecom.ytx.hash;importjava.util.Arrays;importjava.util.HashMap;/** *  题目：two-sum *  *  描述：    Given an array of integers, find two numbers such that they add up to a specific tar

packagecom.ytx.hash;importjava.util.ArrayList;importjava.util.Arrays;/** 题目： 4sum * *     描述： Given an array S of n integers, are there elements a, b, c, *                  and d in

package com.ytx.hash;import java.util.ArrayList;import java.util.Arrays;/** 题目：3sum * *     描述：    Given an array S of n integers, are there elements a, b, c in S such that a + b + c

packagecom.ytx.dp;/** 题目描述：给定一个整数数组，如{-1,3,6,0,-9,2,-5,-1,9,3,-3}，求该数组中的和最大的连续子序列 * *@authoryuantian xin *      *     以下是根据之前dp算法的进一步优化，优化空间，并不需要一个数组来打表，可以用两个变量即可。 */publicclass

packagecom.ytx.array;importjava.util.Arrays;/** 题目：first-missing-positive *      *     描述： Given an unsorted integer array, find the first missing positive integer.                    Fo

packagecom.ytx.array;/** *  题目 ：   next-permutation *  *  描述：    Implement next permutation, which rearranges numbers into the lexicographically *           next greater permutation of num

packagecom.ytx.array;importjava.util.Arrays;/** 题目： 3sum-closest *      *     描述： Given an array S of n integers, find three integers in S such that the sum is *                  closest

packagecom.ytx.array;/** 题目：search-a-2d-matrix *  描述：    Write an efficient algorithm that searches for a value in an  (m x n)  matrix.    This matrix has the following properties:        

packagecom.ytx.array;/** 题目:palindrome-number * *  描述： *     Determine whether an integer is apalindrome. Do this without extra space.             click to show spoilers.            

packagecom.ytx.array;/** 题目：remove-duplicates-from-sorted-array * *     描述：Given a sorted array, remove the duplicates in place such that each *           element appear only once and return

packagecom.ytx.array;importjava.util.ArrayList;importjava.util.Collections;importjava.util.Comparator;/** 题目：merge-intervals * *  描述：    Given a collection of intervals, merge all

packagecom.ytx.array;importjava.util.ArrayList;importjava.util.List;/**  题目：   spiral-matrix *   描述：   Given a matrix of m x n elements (m rows, n columns), *            return all ele

packagecom.ytx.array;importjava.util.ArrayList;/** 题目：spiral-matrix-ii * *     描述： Given an integer n, generate a square matrix filled with elements from 1 to n 2 in spiral order.       

packagecom.ytx.array;/**130题  *  Given a 2D board containing'X'and'O', capture all regions surrounded by'X'.    A region is captured byflipping all'O's into'X's in that surrounded region .

packagecom.ytx.array;/** * best-time-to-buy-and-sell-stock * *     Say you have an array for which the ith element is the price of a given stock on day i.       If you were only permitte

packagecom.ytx.array;/**best-time-to-buy-and-sell-stock-ii * * Say you have an array for which the ith element is the price of a given stock on day i.   Design an algorithm to find the max

packagecom.ytx.array;/**best-time-to-buy-and-sell-stock-iii * *     Say you have an array for which the ith element is the price of a given stock on day i.       Design an algorithm to fin

packagecom.ytx.array;/** *  plus-one * * Given a number represented as an * array of digits, plus one to the number. * *@authoryuantian xin * 给你一个用数组表示的数，求加一之后的结果，结果还是用数组表示。 *

package com.ytx.array;/** * convert-sorted-array-to-binary-search-tree *  * Given an array where elements are sorted in ascending order, convert it to a height balanced BST. *  * @author y

packagecom.ytx.array;/** * convert-sorted-array-to-binary-search-tree * * Given an array where elements are sorted in ascending order, convert it to a height balanced BST. * *@author

packagecom.ytx.array;/** 题目：rotate-image * *  描述:     You are given an n x n 2D matrix representing an image.                    Rotate the image by 90 degrees (clockwise).