题意很明确，先求出一段循环节，再对这段数求出n，

 

一开始我用的vector来求，可是忘记了内存问题，参考了别人的代码，才发现了问题，真是惭愧，向大神们致敬，

 

重新写的一个

 

#include<iostream>

#include<string>

#include<fstream>

using namespace std;

int vis[100], n,num,p;

void cnt(int x, int y)

{

vis[0] = x;

vis[1] = y;

for(int i = 2; i <= 100; i++)

{

int nexta = vis[i-1]+vis[i-2];

if( nexta > 9 )

{

vis[i] = nexta/10;

vis[i+1] = nexta%10;

i++;

}

else

vis[i] = nexta;

if( vis[i-1] == vis[0] && vis[i] == vis[1] )

{

p = i-1;

break;

}

}

num = vis[ (n-1)%p ];

}

int main()

{

ifstream cin("in.txt");

int a, b, T;

cin>>T;

for(int i = 1; i <= T; i++ )

{

cin>>a>>b>>n;

cnt(a,b);

cout<<"Case #"<<i<<": "<<num<<endl;

}

return 0;

}