题目连接：
http://www.codeforces.com/contest/659/problem/A
Description
Vasya lives in a round building, whose entrances are numbered sequentially by integers from 1 to n. Entrance n and entrance 1 are adjacent.
Today Vasya got bored and decided to take a walk in the yard. Vasya lives in entrance a and he decided that during his walk he will move around the house b entrances in the direction of increasing numbers (in this order entrance n should be followed by entrance 1). The negative value of b corresponds to moving |b| entrances in the order of decreasing numbers (in this order entrance 1 is followed by entrance n). If b = 0, then Vasya prefers to walk beside his entrance.
Illustration for n = 6, a = 2, b = - 5.
Help Vasya to determine the number of the entrance, near which he will be at the end of his walk.
Input
The single line of the input contains three space-separated integers n, a and b (1 ≤ n ≤ 100, 1 ≤ a ≤ n, - 100 ≤ b ≤ 100) — the number of entrances at Vasya's place, the number of his entrance and the length of his walk, respectively.
Output
Print a single integer k (1 ≤ k ≤ n) — the number of the entrance where Vasya will be at the end of his walk.
Sample Input
6 2 -5
Sample Output
3
Hint
题意
给你一个环形轨道，你一开始在a，然后你走b步，问你在哪儿。
题解：
这个小心负数的情况，为了避免这个，我直接将a+=100*n，这样就不会有负数的情况了。
代码
#include<bits/stdc++.h>
using namespace std;
int main()
{
long long n,a,b;
cin>>n>>a>>b;a--;
a=a+100*n;
a=a+b;
cout<<a%n+1<<endl;
}
