package com.wgcris.LeetcodeAlgorithm;

import java.util.HashMap;

import java.util.Map;

/*

* leetcode: TwoSum:给出n个数，找出和为一个特定数的两个数，返回数的下标。

*/

public class TwoSum {

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

int[] arr ={2,6,11,15};

int target = 13;

int[] result = twoSum1(arr,target);

System.out.println(result[0]+" "+result[1]);

}

public static HashMap<Integer,Integer> twoSum(int[] arr,int target){

//int[]为给定的数组，target为特定目标数

HashMap<Integer,Integer>hm =new HashMap<Integer,Integer>();

int k=1;

for(int i=0;i<arr.length;i++){

for(int j=i+1;j<arr.length;j++){

if(arr[i]+arr[j]==target){

hm.put(k, i+1);

k++;

hm.put(k,j+1);

k++;

break;

}

}

}

return hm ;

}

public static int[] twoSum1(int[] arr,int target){

int[] result=new int[2];

HashMap<Integer,Integer> hm = new HashMap<Integer,Integer>();

for(int i=0;i<arr.length;i++){

hm.put(arr[i], i);

}

for(int i=0;i<arr.length;i++){

int gap =target-arr[i];

if(hm.get(gap)!=null&&hm.get(gap)!=i){

result[0]=i+1;

result[1]=hm.get(gap)+1;

}

}

return result;

}

}