Triangular Matchstick Number

Namachila November 19, 2025

0 3 2 minutes read

Given a number X which represents the floor of a matchstick pyramid, write a program to print the total number of matchstick required to form pyramid of matchsticks of x floors.

Examples:

Input : X = 1
Output : 3

Input : X = 2
Output : 9

This is mainly an extension of triangular numbers. For a number X, the matchstick required will be three times of X-th triangular numbers, i.e., (3*X*(X+1))/2

C++

// C++ program to find X-th triangular
// matchstick number
 
#include <bits/stdc++.h>
using namespace std;
 
int numberOfSticks(int x)
{
    return (3 * x * (x + 1)) / 2;
}
 
int main() 
{
    cout<<numberOfSticks(7);
    return 0;
}

Java

// Java program to find X-th triangular
// matchstick number
public class TriangularPyramidNumber {
    public static int numberOfSticks(int x)
    {
        return (3 * x * (x + 1)) / 2;
    }
    public static void main(String[] args)
    {
        System.out.println(numberOfSticks(7));
    }
}

Python3

# Python program to find X-th triangular
# matchstick number
 
def numberOfSticks(x):
    return (3 * x * (x + 1)) / 2
     
# main()
print(int(numberOfSticks(7)))

C#

// C# program to find X-th triangular
// matchstick number
using System;
 
class GFG
{
    // Function to ind missing number
    static int numberOfSticks(int x)
    {
        return (3 * x * (x + 1)) / 2;
    }
 
    public static void Main()
    {
        Console.Write(numberOfSticks(7));
    }
}
 
// This code is contributed by _omg

PHP

<?php
// PHP program to find
// X-th triangular
// matchstick number
 
function numberOfSticks($x)
{
    return (3 * $x * ($x + 1)) / 2;
}
 
// Driver code
echo(numberOfSticks(7));
 
// This code is contributed by Ajit.
?>

Javascript

<script>
// javascript program to find X-th triangular
// matchstick number
 
function numberOfSticks( x)
{
    return (3 * x * (x + 1)) / 2;
}
 
   document.write(numberOfSticks(7));
 
// This code is contributed by aashish1995
 
</script>

Output:

Time Complexity: O(1)

Auxiliary Space: O(1)

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