#UVa：324－Factorial Frequencies

利用大數乘法的方式算出每一個階層的答案，並將算出來的答案事先先存起來即可。

C++(0.015)

/*******************************************************/
/* UVa 324 Factorial Frequencies                       */
/* Author: LanyiKnight [at] knightzone.studio             */
/* Version: 2015/05/04                                 */
/*******************************************************/
#include <iostream>
#include <cstdio>
using namespace std;

const int MAXDIGIT = 785;
const int MAXNUMBER = 368;

int main(){
  int num[MAXDIGIT] = {1}, mem[MAXNUMBER][10] = {0};
  mem[0][0] = 1;
  mem[1][1] = 1;
  for( int i = 2 ; i < MAXNUMBER ; ++i ){
    int carry = 0;
    for( int j = 0 ; j < MAXDIGIT ; ++j ){
      num[j] *= i;
      num[j] += carry;
      carry = num[j] / 10;
      num[j] %= 10;
    }

    int upperBound;
    for( upperBound = MAXDIGIT-1 ; upperBound > 0 && num[upperBound] == 0 ; --upperBound );

    for( int j = upperBound ; j >= 0 ; --j ){
      ++mem[i][num[j]];
    }
  }

  int n;
  while( scanf("%d", &n) != EOF && n != 0 ){
    printf("%d! --\n", n);

    for( int i = 0 ; i < 10 ; ++i ){
      if( i == 5 ) printf("\n");
      if( i % 5 == 0 ){
        printf("   ");
      }
      else{
        printf("    ");  
      }

      printf("(%d)%5d", i, mem[n][i]);
    }
    printf("\n");
  }

  return 0;
}