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].

public class Solution {
    public int[] twoSum(int[] nums, int target) {
            if(nums.length<2)
            return nums;
            int[] arr=new int[2];
            Map<Integer,Integer> map=new HashMap<Integer,Integer>();
            for(int i=0;i<nums.length;i++)
            {
                
 
if(!map.containsKey(nums[i])){
                map.put(nums[i],i);
                }
                if(map.containsKey(target-nums[i])&&i!=map.get(target-nums[i]))
                {
                    arr[0]=map.get(target-nums[i]);
                    arr[1]=i;
                      return
 
 arr;   
                }
              
            }
      return arr;      
    }
}

如果有更好解法的朋友歡迎評論。

leetcode第一題