两数之和

public class Solution {
    /*
     * @param numbers : An array of Integer
     * @param target : target = numbers[index1] + numbers[index2]
     * @return : [index1 + 1, index2 + 1] (index1 < index2)
     */
    public int[] twoSum(int[] numbers, int target) {
        HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
        
        for (int i = 0; i < numbers.length; i++) {
            if (map.get(numbers[i]) != null) {
                int[] result = {map.get(numbers[i]) + 1, i + 1};
                return result;
            }
            map.put(target - numbers[i], i);
        }
        
        int[] nums = {};
        return nums;
    }
}