SDNU 1102.小树林(水题）

#include <cstdio>
#include <iostream>
#include <string>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <queue>
#include <map>
#include <vector>
using namespace std;

#define ll long long

unsigned ll a, b, c;//如果不行，就改为ll
unsigned ll sum = 0, s= 0;

 unsigned ll qsm(unsigned ll x, unsigned ll y)
 {
     unsigned ll ans = 1;
     while(y)
     {
         if(y&1)ans = ans*x;
         y /= 2;
         x *= x;
     }
     return ans;
 }

 int main()
 {
     scanf("%llu%llu%llu", &a, &b, &c);
     sum = qsm(c, a);
     sum = (sum-1)*b/(c-1);
     printf("%llu\n", sum);
     return 0;
 }