HDU 1211 RSA逆元高速モードべき乗

/** 
  * url: http://acm.hdu.edu.cn/showproblem.php?pid=1211 RSA
  * Author: Johnsondu
  * Time: 2012-7-28 18:00 around
  * Stratege:   (      ) ,      
  * Status: 6364213	2012-07-28 18:12:54	Accepted	1211	0MS	256K	951 B	C++	johnsondu
*/

#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <stack>
using namespace std ;

typedef __int64 lld ;
lld p, q, e, l ;
lld n, f, pd ;
lld c, M ;

void exGcd (lld a, lld b, lld &d, lld &x, lld &y)
{
	if (b == 0)
	{
		x = 1 ;
		y = 0 ;
		d = a ;
		return ;
	}
	exGcd (b, a%b, d, x, y) ;
	lld tmp = x ;
	x = y ;
	y = tmp - a/b*y ;
}

lld ModPow (lld a, lld pn, lld Mod)
{
	int tmp = 1 ;
	while (pn)
	{
		if (pn&1)
			tmp = tmp*a % Mod ;
		a = (a*a) % Mod ;
		pn >>= 1 ;
	}
	return tmp ;
}

int main () 
{
	lld x, y, d, a, b ;
	while (scanf ("%I64d%I64d%I64d%I64d", &p, &q, &e, &l) != EOF)
	{
		n = p * q ;
		f = (p-1) * (q-1) ;
		exGcd (e, f, d, x, y) ;
		pd = (x % f + f) % f ;
		
		for (int i = 0; i < l; i ++)
		{
			scanf ("%I64d", &c) ;
			M = ModPow (c, pd, n) ;
			printf ("%c", char(M)) ;
		}
		
		printf ("
") ;
	}
	return 0 ;
}