import java.util.*;
class TwoSum {
public static int[] twoSum(int[] nums, int target) {
// make hash
HashMap hash = new HashMap<>();
for (int i = 0; i < nums.length; i++) {
int compl = target - nums[i];
// check if num is value in hash
if (hash.containsKey(compl)){
return new int[] {i, hash.get(compl)};
}
// or add the index and num
else {
hash.put(nums[i], i);
}
}
return new int[] {};
}
public static void main(String[] args) {
int[] nums = {2,7,11,15};
int target = 9;
int[] output = twoSum(nums, target);
System.out.println(Arrays.toString(output));
}
}
/*
* https://leetcode.com/problems/two-sum/description/
* 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]
*/