题解 | #两数之和#

import java.util.*;


public class Solution {
    /**
     *
     * @param numbers int整型一维数组
     * @param target int整型
     * @return int整型一维数组
     */
    public int[] twoSum (int[] numbers, int target) {
        // write code here
        if (numbers == null) return null;
        // 用来存放之前扫描过的元素,key-存储的值，value-存储的索引
        Map<Integer, Integer> map = new HashMap<>();
        for (int i = 0; i < numbers.length; i++) {
            Integer idx = map.get(target - numbers[i]);
            if (idx != null) return new int[] {idx+1, i+1};
            map.put(numbers[i], i);
        }
        return null;
    }
}

解题思想：哈希存值+结果值判断