TwoSumSolution2.java

import java.util.Arrays;
import java.util.HashMap;

class TwoSumSolution2{
  static int[] findTwoSumSolution2(int[] nums, int target) {
    HashMap<Integer,Integer> map = new HashMap<>();
    for(int i = 0; i < nums.length; i++){
      Integer temp = (target - nums[i]);
      if(map.containsKey(temp)){
        int result [] = { map.get(temp), i };
        return result;
      }
      map.put(nums[i], i);
    }
    return null;
  }

  public static void main(String [] args) {
    int testCase1nums[] = {5, 7, 12,1};
    int testCase1Target = 12;

    int testCase2nums[] = {3, 5, 0};
    int testCase2Target = 6;

    int testCase3nums[] = {0, 3};
    int testCase3Target = 3;

    int testCase4nums[] = {0, -1, 2, -3, 1};
    int testCase4Target = -2;

    int testCase5nums[] = {4, -11, 22, -23, 31};
    int testCase5Target = -20;
    System.out.println(Arrays.toString(findTwoSumSolution2(testCase1nums,testCase1Target)));
    System.out.println(Arrays.toString(findTwoSumSolution2(testCase2nums,testCase2Target)));
    System.out.println(Arrays.toString(findTwoSumSolution2(testCase3nums,testCase3Target)));
    System.out.println(Arrays.toString(findTwoSumSolution2(testCase4nums,testCase4Target)));
    System.out.println(Arrays.toString(findTwoSumSolution2(testCase5nums,testCase5Target)));
  }
}