Pattern 10

Problem

Geek is very fond of patterns. Once, his teacher gave him a pattern to solve. He gave Geek an integer n and asked him to build a pattern.

Help Geek to build a star pattern.

Examples:

Example 1:

Input: 5
Output:
* 
* * 
* * * 
* * * * 
* * * * *
* * * *
* * *
* *
*

Example 2:

Input: 3
Output:
* 
* * 
* * * 
* *
*

Your task:

You don't need to input anything. Complete the function printTriangle() which takes an integer n as the input parameter and prints the pattern.

• Expected Time Complexity: $O(n^2)$
• Expected Auxiliary Space: $O(1)$

Constraints:

• $1 <= n <= 1000$

Solution

Python

def printTriangle(self, n):
    for i in range(1, n+1):
        print('* ' * i)
    for i in range(n-1, 0, -1):
        print('* ' * i)

Java

void printTriangle(int n) {
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            System.out.print("* ");
        }
        System.out.println();
    }
    for (int i = n - 1; i >= 1; i--) {
        for (int j = 1; j <= i; j++) {
            System.out.print("* ");
        }
        System.out.println();
    }
}

C++

void printTriangle(int n) {
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            std::cout << "* ";
        }
        std::cout << std::endl;
    }
    for (int i = n - 1; i >= 1; i--) {
        for (int j = 1; j <= i; j++) {
            std::cout << "* ";
        }
        std::cout << std::endl;
    }
}

C

void printTriangle(int n) {
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= i; j++) {
            printf("* ");
        }
        printf("\n");
    }
    for (int i = n - 1; i >= 1; i--) {
        for (int j = 1; j <= i; j++) {
            printf("* ");
        }
        printf("\n");
    }
}

• Time Complexity: $O(n^2)$
• Auxiliary Space: $O(1)$