Leetcode 1 Two Sum Java Solution

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].

Solution:

class Solution {
    public int[] twoSum(int[] nums, int target) {
        Map<Integer, Integer> temp = new HashMap<Integer, Integer>();
        for( int i = 0;i<nums.length;i++){
           if( temp.containsKey(nums[i])){
            int[] returnVal = new int[2];
               returnVal[0] = temp.get(nums[i]);
               returnVal[1] = i;
               return returnVal;
           }
            temp.put(target-nums[i], i);
        }
        return null;
    }
}