Two Sum 2015年6月8日

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

Runtime: 475 ms

本题java语言理想运行时间是在100-200ms之间

Arrays.sort(nums);可以对数组进行排序，但在本题意义不大，排完序之后数组下标就乱啦。

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