[LeetCode] Two Sum

题目

Given an array of integers, find two numbers such that they add up to a specific target number.

The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2. Please note that your returned answers (both index1 and index2) are not zero-based.

You may assume that each input would have exactly one solution.

Input: numbers={2, 7, 11, 15}, target=9

Output: index1=1, index2=2

思路

这道题比较简单，需要注意的是题目中的一些约束：1）index1小于index2；2）index1和index2都不是zero-based。以及题目中假设每个输入只有一个结果，所以直接上双层循环解决。

代码

public class Solution {
    public int[] twoSum(int[] nums, int target) {
        int[] result = new int[2];
        for(int i = 0;i < nums.length;i++){
            for(int j = i + 1;j < nums.length;j++){
                if(nums[i] + nums[j] == target){
                    result[0] = i + 1;
                    result[1] = j + 1;
                    return result;
                }
            }
        }
        return result;
    }
}