poj 2447 代码改正

//之前2447贴错了代码，表示很sorry

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

#include <time.h>

#define MAXN 10

#define Ct 16381

#define I64 long long

I64 multi(I64 a, I64 b, I64 n){

     I64 tmp = a % n, s = 0;

   while(b){

         if(b & 1) s = (s + tmp) % n;

              tmp = (tmp + tmp) % n;

            b >>= 1;

    }

 return s;

}

I64 Pow(I64 a, I64 b, I64 n){

 I64 tmp = a % n, s = 1;

   while(b){

         if(b & 1) s = multi(s, tmp, n);

           tmp = multi(tmp, tmp, n);

         b >>= 1;

    }

 return s;

}

I64 gcd(I64 a, I64 b){

        return b ? gcd(b, a % b) : a;

}

I64 Ext_Gcd(I64 a, I64 b, I64 &x, I64 &y){

        if(!b){

           x = 1, y = 0;

             return a;

 }

 I64 r = Ext_Gcd(b, a % b, x, y);

  I64 t = x; x = y; y = t - a / b * y;

      return r;

}

I64 pollard_rho(I64 n, I64 c){

        I64 x, y, d, i = 1, k = 2;

        srand((I64)time(0));

      x = ((I64) rand()) % (n - 1) + 1;

 y = x;

    while(1){

         i ++;

             x = (multi(x, x, n) + c) % n;

             d = gcd(y - x + n, n);

            if(d != 1 && d != n) return d;

            if(y == x) return n;

              if(i == k) y = x, k <<= 1;

  }

}

int main(){

   I64 C, E, N, D, M, P, Q, T, X, Y;

 while(~scanf("%I64d %I64d %I64d", &C, &E, &N)){

           P = pollard_rho(N, Ct);

           Q = N / P;

                T = (P - 1) * (Q - 1);

            Ext_Gcd(E, T, X, Y);

              D = (X + T) % T;

          M = Pow(C, D, N);

         printf("%lld\n", M);

      }

 return 0;

}