leetcode_1. 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].
解题代码：class Solution {
public int[] twoSum(int[] nums, int target) {
int [] a= 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){
a[0]=i;
a[1]=j;
break;
}
}
}
return a;
}
}