转圈游戏

luogu 1965

题目大意

求$(x+m\times 10^k)\%n$

输入样例

10 3 4·5

输出样例

5

数据范围

$1<n<10000000<m<n,1⩽x⩽n,0<k<10^9$

解题思路

快速幂计算$10^k$,然后直接计算即可

代码

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define ll long long
#define wyc n
using namespace std;
ll n, m, k, x;
ll Counting(ll x, ll y)
{ll g = 1;while(y){if (y & 1) g = g * x % wyc;x = x * x % wyc;y >>= 1;}return g;
}
int main()
{scanf("%lld%lld%lld%lld", &n, &m, &k, &x);k = Counting(10ll, k);x = (x + m * k % wyc) % wyc;printf("%lld", x);return 0;
}