Jzzhu and Sequences題解
阿新 • • 發佈:2018-11-22
Jzzhu has invented a kind of sequences, they meet the following property:
You are given x and y, please calculate fn modulo 1000000007 (109 + 7).
InputThe first line contains two integers x and y (|x|, |y| ≤ 109). The second line contains a single integer n (1 ≤ n ≤ 2·109).
Output a single integer representing fn modulo 1000000007 (109 + 7).
Example Input2 3 3Output
1Input
0 -1 2Output
1000000006
In the first sample, f2 = f1 + f3, 3 = 2 + f3, f3 = 1.
In the second sample, f2 = - 1; - 1 modulo (109 + 7) equals (109 + 6).
AC C++
#include <iostream> #define m 1000000007 using namespace std ; long long a,b,n; int main() { cin>>a>>b>>n; n--; n=n % 6; long long ans=0; switch(n) { case 0: { ans=(a+m)%m; break; } case 1: { ans=(b+m)%m; break; } case 2: { ans=(b-a+2*m)%m; break; } case 3: { ans=(m-a)%m; break; } case 4: { ans=(m-b)%m; break; } case 5 : { ans=(a-b+2*m)%m; break; } } cout<<ans<<endl; return 0; }