1068. Sum
Time limit: 2.0 second
Memory limit: 64 MB
Memory limit: 64 MB
Your task is to find the sum of all integer numbers lying between 1 and N inclusive.
Input
The input consists of a single integer N that is not greater than 10000 by it's absolute value.
Output
Write a single integer number that is the sum of all integer numbers lying between 1 and N inclusive.
Sample
input | output |
---|---|
-3 | -5 |
Problem Source: 2000-2001 ACM Northeastern European Regional Programming Contest (test tour)
Tags: problem for beginners
Difficulty: 42
Solution :
#include<stdio.h>
int main(){
int n,N,ans;
scanf("%d",&N);
if(N > 1){
n=N;
}else{
n=-1*N+2;
}
ans=(n*(N+1))/2;
printf("%d\n",ans);
return 0;
}