LeetCode -1 Two sum

准备慢慢的刷刷Leetcode，慢慢记录下，欢迎大家讨论。

难度：简单

题干：

Two sum

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].

我的解答（java），虽然通过了LeetCode的测试，但是 target-nums[i] 是有可能超过int最大最小值得，没有校验。

public class Solution {
    public int[] twoSum(int[] nums, int target) {
        int[] rs = null ;
        Map<Integer,Integer> map = new HashMap<>();
        for(int i=;i<nums.length;i++){
            if(map.containsKey(target-nums[i])){
                rs = new int[]{map.get(target-nums[i]),i};
                break;
            }else{
                map.put(nums[i], i);
            }
        }
        return rs ;
    }
}
           

时间复杂度O（n），空间复杂度也是O（n）。有更好更酷的解答方式，欢迎大家讨论！