704983. Sum of First N Natural Numbers
Easy
Sum of First N Natural Numbers
Slug: reverse-coding2452 Difficulty: Easy Id: 704983 Topic Tags: Mathematical, Algorithms Company Tags: None
Summary
This problem is about finding the sum of the first n natural numbers. The key concept involved here is mathematical calculation.
Detailed Explanation
To solve this problem, we can use the formula for the sum of an arithmetic series:
1 + 2 + 3 + ... + n = n*(n+1)/2
This formula is derived from the equation of a triangle with n sides. Each side represents a term in the sequence and the area of the triangle represents the sum.
Here's a step-by-step breakdown of the solution:
- Calculate the value of
n. - Use the above formula to calculate the sum.
- Return the calculated sum.
Time complexity: O(1) as we are performing a constant number of operations. Space complexity: O(1) as we are not using any extra space that scales with the input size.
Optimized Solutions
Java
public class SumOfFirstN {
public static int calculateSum(int n) {
return n*(n+1)/2;
}
}