Hollow Half Pyramid Pattern Using Numbers

A hollow half-pyramid pattern using numbers is a type of pattern that seems like a pyramid shape mostly it is considered a star pattern but here we will be creating using numbers. 

Hollow half-pyramid pattern using numbers

Program to print the following pattern of a half pyramid for N.

Example: 

Input: N = 5
1
1 2
1   3
1     4
1 2 3 4 5

Below is the implementation of the above approach:

C++

// C++ program print hollow half pyramid
// pattern using numbers
#include <iostream>
using namespace std;

void pattern(int N)
{
    int i, j, k = 0;
    // loop to print number from 1 to N
    for (i = 1; i <= N; i++) {
        // For loop to display number upto i
        for (j = 1; j <= i; j++) {
            if (j == 1 || j == i || i == N)
                cout << j << " ";
            else
                cout << "  ";
        }
        cout << endl;
    }
}
// Driver Code
int main()
{
    int N = 5;
    // Function Call
    pattern(N);
    return 0;
}

C

// C program print hollow half pyramid
// pattern using numbers
#include <stdio.h>

// Pattern function
void pattern(int N)
{
    int i, j, k = 0;

    // loop to print number from 1 to N
    for (i = 1; i <= N; i++) {
        // For loop to display number upto i
        for (j = 1; j <= i; j++) {
            if (j == 1 || j == i || i == N)
                printf("%d ", j);
            else
                printf("  ");
        }
        printf("\n");
    }
}

// Driver Code
int main()
{
    int N = 5;
    // Function Call
    pattern(N);
    return 0;
}

Java

// Java program print hollow half pyramid
// pattern using numbers
import java.io.*;

class GFG {
    // Pattern function
    static void pattern(int N)
    {
        int i, j, k = 0;

        // loop to print number from 1 to N
        for (i = 1; i <= N; i++) {
            // For loop to display number upto i
            for (j = 1; j <= i; j++) {
                if (j == 1 || j == i || i == N)
                    System.out.print(j + " ");
                else
                    System.out.print("  ");
            }
            System.out.println();
        }
    }

    // Main Function
    public static void main(String[] args)
    {
        // Variable declared
        int N = 5;

        // Pattern function called
        pattern(N);
    }
}

C#

using System;

class Program
{
    static void Pattern(int N)
    {
        // Loop to print numbers from 1 to N
        for (int i = 1; i <= N; i++)
        {
            // For loop to display numbers up to i
            for (int j = 1; j <= i; j++)
            {
                if (j == 1 || j == i || i == N)
                    Console.Write(j + " ");
                else
                    Console.Write("  ");
            }
            Console.WriteLine();
        }
    }

    static void Main(string[] args)
    {
        int N = 5;
        // Function Call
        Pattern(N);
    }
}

Javascript

// Function to print a hollow 
// half pyramid pattern using numbers
function printHollowHalfPyramid(N) {

  // Loop to print numbers from 1 to N
  for (let i = 1; i <= N; i++) {

    // Loop to display numbers up to i
    for (let j = 1; j <= i; j++) {

      // Print number if it's the first or last one in the row or if it's the last row
      if (j === 1 || j === i || i === N) {
        process.stdout.write(`${j} `); // Use process.stdout.write() to print without a newline
      } else {
        process.stdout.write("  "); // Print two spaces for hollow parts
      }
    }

    // Move to a new line after each row is printed
    process.stdout.write("\n");
  }
}

// Main code block
let N = 5; // Define the size of the pyramid
printHollowHalfPyramid(N); // Call the function to print the pattern

Python3

# Python program print hollow half pyramid
# pattern using numbers

# pattern function


def pattern(N):
    for i in range(1, N+1):
        for j in range(1, i+1):
            if j == 1 or j == i or i == N:
                print(j, end=" ")
            else:
                print(" ", end=" ")
        print()


# Driver code
if __name__ == "__main__":
    N = 5
    pattern(N)

Output

1 
1 2 
1   3 
1     4 
1 2 3 4 5 

Time complexity O(N²) 

Reason: we are looping through the rows and columns of the pattern.

Space complexity O(1)

Reason: This algorithm does not require any additional space.

Hollow Inverted Half Pyramid Pattern using numbers

Printing an Inverted pyramid of a pattern is mostly the same as printing the pyramid normally just changes in a few conditions and we are all done. Let us check the code.

Example: 

input: N = 6
1 2 3 4 5 6
2       6 
3     6
4   6
5 6
6

C++

// C++ program to print hollow inverted half pyramid
// pattern using numbers
#include <iostream>
using namespace std;

void pattern(int N)
{
    int i, j, k = 0;
    // loop to print number from 1 to N
    for (i = 1; i <= N; i++) {
        // For loop to display number from i to N
        for (j = i; j <= N; j++) {
            if (i == 1 || j == i || j == N)
                cout << j << " ";
            else
                cout << "  ";
        }
        cout << endl;
    }
}

// Driver Code
int main()
{
    int N = 6;
    // Function Call
    pattern(N);
    return 0;
}

C

  // C program to print hollow inverted half pyramid
  // pattern using numbers
  #include <stdio.h>

  void pattern(int N)
  {
      int i, j, k = 0;
      // loop to print number from 1 to N
      for (i = 1; i <= N; i++) {
          // For loop to display number from i to N
          for (j = i; j <= N; j++) {
              if (i == 1 || j == i || j == N)
                  printf("%d ", j);
              else
                  printf("  ");
          }
          printf("\n");
      }
  }

  // Driver Code
  int main()
  {
      int N = 6;
      // Function Call
      pattern(N);
      return 0;
  }

Java

// Java program to print hollow inverted half pyramid
// pattern using numbers
import java.io.*;

// Driver Class
class GFG {
    static void pattern(int N)
    {
        int i, j, k = 0;
        // loop to print number from 1 to N
        for (i = 1; i <= N; i++) {
            // For loop to display number from i to N
            for (j = i; j <= N; j++) {
                if (i == 1 || j == i || j == N)
                    System.out.print(j + " ");
                else
                    System.out.print("  ");
            }
            System.out.println();
        }
    }

    // Main function
    public static void main(String[] args)
    {
        int N = 6;

        // Pattern function called
        pattern(N);
    }
}

C#

// C# program for the above approach
using System;

public class GFG {
    // Function to print hollow inverted half pyramid
    // pattern using numbers
    static void Pattern(int N)
    {
        // loop to print number from 1 to N
        for (int i = 1; i <= N; i++) {
            // For loop to display number from i to N
            for (int j = i; j <= N; j++) {
                if (i == 1 || j == i || j == N)
                    Console.Write(j + " ");
                else
                    Console.Write(" ");
            }
            Console.WriteLine();
        }
    }

    // Driver Code
    public static void Main()
    {
        int N = 6;
        // Function Call
        Pattern(N);
    }
}

// This code is contributed by Susobhan Akhuli

Javascript

// Function to print a hollow inverted 
// half pyramid pattern using numbers
function printHollowInvertedHalfPyramid(N) {

  // Loop to print numbers from 1 to N
  for (let i = 1; i <= N; i++) {

    // Loop to display numbers from i to N
    for (let j = i; j <= N; j++) {

      // Print number if it's the first row, or if it's on the diagonal, or if it's on the last column
      if (i === 1 || j === i || j === N) {
        process.stdout.write(`${j} `); // Use process.stdout.write() to print without a newline
      } else {
        process.stdout.write("  "); // Print two spaces for hollow parts
      }
    }

    // Move to a new line after each row is printed
    process.stdout.write("\n");
  }
}

// Main code block
let N = 6; // Define the size of the pyramid
printHollowInvertedHalfPyramid(N); // Call the function to print the pattern

Python3

# python program to print hollow inverted half pyramid
# pattern using numbers

#pattern function
def pattern(N):
    for i in range(1, N+1):
        for j in range(i, N+1):
            if i == 1 or j == i or j == N:
                print(j, end=" ")
            else:
                print(" ", end=" ")
        print()

# Driver code
if __name__ == "__main__":
    N = 6
    pattern(N)

Output

1 2 3 4 5 6 
2       6 
3     6 
4   6 
5 6 
6 

Time complexity O(N²) 

Reason: we are looping through the rows and columns of the pattern.

Space complexity O(1)

Reason: This algorithm does not require any additional space.