Sum of Natural Numbers

Published at25 Jul 2026

Math Basic Operations Easy 0 views

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Given a positive integer n, return the sum of all natural numbers from 1 to n (inclusive). Use the formula n * (n + 1) / 2 instead of a loop for O(1) time.

Example Input & Output

Example 1

Input

Output

Explanation

1+2+...+10=55

Example 2

Input

Output

Explanation

1+2+3=6

Example 3

Input

Output

Explanation

1+2+3+4+5=15

Example 4

Input

Output

Explanation

Empty sum

Example 5

Input

Output

Explanation

Just 1

Algorithm Flow

Recommendation Algorithm Flow for Sum of Natural Numbers

Solution Approach

function solution(n) {
  return n * (n + 1) / 2;
}

Best Answers
These are the verified best solutions for this Challenge. You can use them as a reference to improve your solution.

java

class Solution {
    public int solution(int n) {return n*(n+1)/2;}
}

javascript

function solution(n){return n*(n+1)/2;}

php

<?php
function solution($n){return$n*($n+1)/2;}

python

def solution(n):return n*(n+1)//2

rust

fn solution(n:i32)->i32{n*(n+1)/2}

typescript

function solution(n:number):number{return n*(n+1)/2;}

Sum of Natural Numbers

Example Input & Output

Algorithm Flow

Solution Approach

Best Answers
These are the verified best solutions for this Challenge. You can use them as a reference to improve your solution.

Solutions Coming Soon

Related Math Challenges

GCD with Euclidean Algorithm

Prime Number Check

Comments (0)

Join the Discussion

Sum of Natural Numbers

Example Input & Output

Algorithm Flow

Solution Approach

Best AnswersThese are the verified best solutions for this Challenge. You can use them as a reference to improve your solution.

Solutions Coming Soon

Related Math Challenges

GCD with Euclidean Algorithm

Prime Number Check

Comments (0)

Join the Discussion

Best Answers
These are the verified best solutions for this Challenge. You can use them as a reference to improve your solution.