class Solution {
    public int[] twoSum(int[] nums, int target) {
       Map<Integer, Integer> map = new HashMap<Integer, Integer>();
       for(int i=0; i<nums.length; i++) {
           int tmp = target - nums[i];
           if(map.containsKey(tmp)) {
               return new int[]{map.get(tmp), i};
           }
           map.put(nums[i],i);
       }
       throw new RuntimeException("No solution");
    }
}