2513: 信息学奥赛一本通T1615-序列的第 k 个数

解题思路:

注意事项:

参考代码:

#include <iostream>

using namespace std;

const long long M=200907;

long long quickpow(long long a,long long b){

long long ret=1;

while(b){

if(b%2==1) ret=(ret*a%M)%M;

a=a*a%M;

b/=2;

}

return ret%M;

}

long long a,b,c;

long long k;

long long t;

int main(){

cin>>t;

while(t--){

cin>>a>>b>>c>>k;

if(b-a==c-b) {

long long d=(b-a)%M;

cout<<((k-1)%M*d+a%M)%M<<endl;;

}

else {

long long d=b/a%M;

cout<<(quickpow(d,k-1)*a%M)%M<<endl;

}

}

return 0;

}