Sum 1 to N

Sum 1 to N

Easy PHP PHP Variables 19 views
Explanation Complexity

Problem Statement

Given n, print the sum 1+2+...+n.

Input Format

One integer n.

Output Format

One integer sum.

Example

5
15

Constraints

1

Input / Output Format

Input Format
One integer n.
Output Format
One integer sum.
Constraints
1

Examples

Input:
5
Output:
15

Example Solution (Public)

PHP 
<?php
$inputText=trim(stream_get_contents(STDIN));
if($inputText==='') exit;
$n=intval($inputText);
echo intdiv($n*($n+1),2);
?>

Official Solution Code

<?php
$inputText=trim(stream_get_contents(STDIN));
if($inputText==='') exit;
$n=intval($inputText);
echo intdiv($n*($n+1),2);
?>
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Output

                                        

                                    

                                    

                                        

                                                                                    
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