DEV Community

Bulbul Ahmed
Bulbul Ahmed

Posted on

Day 01 - Two Sum Problems

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

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

You can return the answer in any order.

Example 1:

Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].
Example 2:

Input: nums = [3,2,4], target = 6
Output: [1,2]
Example 3:

Input: nums = [3,3], target = 6
Output: [0,1]
**
For practice :
Solution: **

package sixtyDaysChallange;

import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

public class TwoSum {

    public static void main(String[] args) {
        int[] nums = {3,2,4};int  target = 6;
        int[] ints = twoSum(nums, target);
        System.out.println(Arrays.toString(ints));
    }

    public static int[] twoSum(int[] nums, int target) {

        Map<Integer,Integer> containsMap = new HashMap<>();
        for(int i=0;i<nums.length;i++){
            int complement = target-nums[i];

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

    }
}
Enter fullscreen mode Exit fullscreen mode

Top comments (0)