public class Solution {
  public int[] twoSum(int[] nums, int target) {
    int n = nums.length;
    for(int i=0; i<n;i++){
      for(int j=i+1; j<n;j++){
        if(nums[i] + nums[j] == target){
          return new int[]{i, j};
        }
      }
    }
    return null;
  }
}