Star Pattern Printer - Problem

Print a right-angled triangle pattern of stars with N rows.

The i-th row should contain exactly i stars, where i ranges from 1 to N.

Each row should be printed on a separate line with no trailing spaces.

Input & Output

Example 1 — Basic Triangle

$ Input: n = 4

› Output: * ** *** ****

💡 Note: Row 1 has 1 star, row 2 has 2 stars, row 3 has 3 stars, row 4 has 4 stars

Example 2 — Minimum Size

$ Input: n = 1

› Output: *

💡 Note: Single row with single star

Example 3 — Larger Triangle

$ Input: n = 5

› Output: * ** *** **** *****

💡 Note: Five rows with 1, 2, 3, 4, and 5 stars respectively

Constraints

1 ≤ n ≤ 1000

Visualization

Tap to expand

Asked in

T TCS 15 I Infosys 12

The key insight is using nested loops where the outer loop controls the row number and the inner loop prints exactly that many stars. Best approach uses string multiplication for cleaner code. Time: O(n²), Space: O(1) for basic approach.

Common Approaches

✓ Nested Loops

⏱️ Time: O(n²) Space: O(1)

Use an outer loop to iterate through each row from 1 to N, and an inner loop to print exactly i stars for the i-th row. After each row, print a newline character.

String Multiplication

⏱️ Time: O(n²) Space: O(n)

Instead of using an inner loop to print individual stars, use string multiplication to create a string of i stars for row i, then print the entire row at once.

Nested Loops — Algorithm Steps

Step 1: Loop through rows 1 to N
Step 2: For each row i, loop from 1 to i and print a star
Step 3: After each row, print a newline

Visualization

Tap to expand

Step-by-Step Walkthrough

Row 1

Outer loop i=1, inner loop prints 1 star

Row 2

Outer loop i=2, inner loop prints 2 stars

Continue

Pattern continues until row N

Code -

solution.c — C

#include <stdio.h>

void solution(int n) {
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j < i; j++) {
            printf("*");
        }
        printf("\n");
    }
}

int main() {
    int n;
    scanf("%d", &n);
    solution(n);
    return 0;
}

Time & Space Complexity

Time Complexity

⏱️

O(n²)

Nested loops: outer loop runs n times, inner loop runs 1+2+3+...+n = n(n+1)/2 times total

⚠ Quadratic Growth

Space Complexity

O(1)

Only uses a few variables, no extra data structures needed

⚡ Linearithmic Space

12.0K Views

High Frequency

~5 min Avg. Time

450 Likes

Ln 1, Col 1

Smart Actions

💡 Explanation

AI Ready

💡 Suggestion Tab to accept Esc to dismiss

// Output will appear here after running code

Code Editor Closed

Click the red button to reopen

Star Pattern Printer - Problem

Input & Output

Constraints

Visualization

Related Problems

Common Approaches

Nested Loops — Algorithm Steps

Visualization

Code -

Time & Space Complexity

Select Compiler