#include <iostream.h> 
#include <stdlib.h> 

int factorial(long int N, long int M) { 
  long int i, j, result, dp; 

  dp=0; result = 1; 

  for(i = N-M+1; i <= N; i++) { 
    j = i;                 
    while (! (j % 2)) { j /= 2; dp++; } 
    while (! (j % 5)) { j /= 5; dp--; } 
    result = (result * (j % 10)) % 10; 
  } 

  for(i = 1; i <= dp; i++) { result = (result * 2) %10; } 

  return result; 
} 

void main() { 
  long int N, M; 

  while (1){ 
      cin >> N >> M; 
      if(!cin) break; 
      cout << factorial(N, M) << endl; 
  } 
} 

• Re:这样还超时，难道要用查表法... (27) math_scut 2007-09-30 21:54:23
• Re:这样还超时，难道要用查表法... (638) zbleach 2008-09-08 15:25:35
  • Re:这样还超时，难道要用查表法... (85) zbleach 2008-09-08 15:28:27
• Re:这样还超时，难道要用查表法... (11) SongLijun 2009-08-08 08:41:50