Two Sum | LeetCode Solution

Hello readers, today we are going to solve Two Sum LeetCode Solution.

Task

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]
Output: 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]

Constraints

• 2 <= nums.length <= 104
• -109 <= nums[i] <= 109
• -109 <= target <= 109
• Only one valid answer exists.

Follow Up: Can you come up with an algorithm that is less than O(n2) time complexity?

Solution - Two Sum | LeetCode Solution 

Python 3

class Solution:
    def twoSum(self, nums: List[int], target: int) -> List[int]:
         seen = {}
         for i, v in enumerate(nums):
            remaining = target - v
            if remaining in seen:
                return [seen[remaining], i]
            seen[v] = i
         return []

C++

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        map<int,int> m;
        vector<int> v;
        for(int i=0;i<nums.size();i++)
        {
            if(m.find(target-nums[i])!=m.end())
            {
                v.push_back(m[target-nums[i]]);
                v.push_back(i);
                return v;
            }
            m[nums[i]]=i;
        }
        return v;
    }
};

Disclaimer: The above Problem (Two Sum) is generated by LeetCode but the Solution is Provided by Sloth Coders. This tutorial is only for Educational and Learning Purpose.