Print star pattern count
Easy
Java
Control Flow
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Problem Statement
Task: return total stars printed in a triangle of height n (1+2+...+n).
Input Format
An integer n (height of the triangle).
Output Format
An integer: total number of stars printed.
Example
4
10
Constraints
• n ≥ 1
Concept Explanation
A triangle of height n prints:
1 + 2 + 3 + ... + n stars.
This is the sum of first n natural numbers.
1 + 2 + 3 + ... + n stars.
This is the sum of first n natural numbers.
Step-by-Step Explanation
1.Read integer n.
2.Initialize total = 0.
3.Loop i from 1 to n.
4.Add i to total.
5.After loop ends, return total.
2.Initialize total = 0.
3.Loop i from 1 to n.
4.Add i to total.
5.After loop ends, return total.
Concept Explanation
A triangle of height n prints:
1 + 2 + 3 + ... + n stars.
This is the sum of first n natural numbers.
1 + 2 + 3 + ... + n stars.
This is the sum of first n natural numbers.
Step-by-Step Explanation
1.Read integer n.
2.Initialize total = 0.
3.Loop i from 1 to n.
4.Add i to total.
5.After loop ends, return total.
2.Initialize total = 0.
3.Loop i from 1 to n.
4.Add i to total.
5.After loop ends, return total.
Input / Output Format
Input Format
An integer n (height of the triangle).
Output Format
An integer: total number of stars printed.
Constraints
• n ≥ 1
Examples
Input:
4
Output:
10
Example Solution (Public)
static long totalStars(int n){return 1L*n*(n+1)/2;}
Official Solution Code
static long totalStars(int n){return 1L*n*(n+1)/2;}
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