给定一个整数数组，返回两个数字的索引，使它们相加到特定目标。

给定一个整数数组，返回两个数字的索引，使它们相加到特定目标。
您可以假设每个输入只有一个解决方案，并且您可能不会两次使用相同的元素。

Example:
Given nums = [2, 7, 11, 15], target = 9,
Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

Java代码如下：

package leetcode;

/**
 * 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.
 */
public class TwoSum {

    public static int[] twoSum(int[] nums, int target) {
        int[] a = new int[2];
        Boolean flag = false;
        for(int i=0;i<nums.length;i++){
            for(int j=i+1;j<nums.length;j++){
                int sum = nums[i]+nums[j];
                if(sum==target){
                    a[0] = i;
                    a[1] = j;
                    flag = true;
                    break;
                }
            }
            if(flag){
                break;
            }
        }
        return a;
    }

    public static void main(String[] args) {
        int[] nums = {2, 7, 11, 15};
        System.out.println(twoSum(nums,9));
    }

}