YoungProgrammer

Lesson: 18
Problem: 10079
Title: Pizza Cutting
Difficulty Level: 1.5
Date: Jan 25, 2009
Site: UVA

Another easy problem if you can figure out the formula. Take a pen and a piece of paper and try to figure out. If you fail, try to find from this source code:

Solution:

 #include<stdio.h>
 #include<math.h>
 
 long long N;
 void main() {
 	long long  x;
 	while(scanf("%lld",&N) == 1) {
 		if(N<0) break;
         x = N * N + N;
 		x = x/2 + 1;
 		printf("%lld\n",x);
 	}
 }