TwoIntegerSum.java

/**
* Given an array of integers nums and an integer target, return the indices i and j such that nums[i] + nums[j] == target and i != j.

* You may assume that every input has exactly one pair of indices i and j that satisfy the condition.

* Return the answer with the smaller index first.

* Example 1:

* Input: 
* nums = [3,4,5,6], target = 7

* Output: [0,1]
**/

class TwoIntegerSum 
{
 public int[] twoSum(int[] nums, int target) 
 {
 HashMap<Integer, Integer> map = new HashMap<>();

 for(int i = 0; i < nums.length; i++)
 {
 int nPoints = target - nums[i];

 if(map.containsKey(nPoints))
 {
 return new int[] {map.get(nPoints), i};
 }
 map.put(nums[i], i);
 }
 return new int[] {};
 }
}