一. 链接和题目简单介绍

　　　　　　链接：

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

Example:

Given nums = [2, 7, 11, 15], target = 9,Because nums[0] + nums[1] = 2 + 7 = 9,return [0, 1].

二. 分析

　　用哈希map 应该会快点

 

三. 代码

　Java：

public int[] twoSum(int[] nums, int target) {    Map
     
       map = new HashMap<>();    for(int i=0 ; i < nums.length ; i++){        map.put(nums[i],i);    }    for (int i = 0;i < nums.length; i++){        int complement = target - nums[i];    if (map.containsKey(complement)) {        return new int [] { i , map.get(complement)};        }    }    throw new IllegalArgumentException("No two sum solution");}
     

 

　　JS：

const twoSum = function(nums, target) {    const comp = {};    for(let i=0; i
     
      =0){            return [ comp[nums[i] ] , i]        }        comp[target-nums[i]] = i    }};