Two Sum

Two Sum hash table

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].

Two Sum Solution

public class TwoSum {
    public int[] twoSum(int[] nums, int target) {
        int[] result = new int[2];

        HashMap<Integer, Integer> map = new HashMap<>();

        for(int i = 0; i < nums.length; i++) {
            if(map.containsKey(target - nums[i])) {
                result[1] = i;
                result[0] = map.get(target - nums[i]);

                return result;
            }

            map.put(nums[i], i);
        }

        return result;
    }
}

Last modified October 4, 2020