twoSum.java

// Given an array of integers, return indices of the two numbers such that they add up to a specific target.

// You may assume that each input would have exactly one solution, and you may not use the same element twice.

// Example:

// Given nums = [2, 7, 11, 15], target = 9,

// Because nums[0] + nums[1] = 2 + 7 = 9,
// return [0, 1].

class Solution {
    public int[] twoSum(int[] nums, int target) {
        int[] res = new int[2];
        int numsLen = nums.length;
        
        HashMap<Integer, Integer> map = new HashMap<>();

        for(int i =0; i<numsLen; i++){
          map.put(nums[i], i);
        }
        
        for(int i = 0; i< numsLen; i++){
            if(map.containsKey(target - nums[i]) && map.get(target - nums[i]) != i){
                res[0] = i;
                res[1] = map.get(target - nums[i]);
            }
        }
        
return res;}

}