UVa 628 - Passwords

Accepted date: 2012-11-08
Ranking (as of 2013-01-20): 24
Language: C++

/*
  UVa 628 - Passwords

  To build using Visual Studio 2008:
    cl -EHsc -O2 UVa_628_Passwords.cpp
*/

#include <cstdio>
#include <cstring>
using namespace std;

const int nr_words_max = 100, nr_word_chars_max = 256;
const int nr_rule_chars_max = 256;
char words[nr_words_max][nr_word_chars_max];
char password[nr_word_chars_max * nr_rule_chars_max];

void print_password(int ri, int rlength, const char* rule,
  int wi, int wlength, int pi)
{
  if (ri == rlength)
    printf("%s\n", password);
  else if (rule[ri] == '#') {
    strcpy(password + pi, words[wi]);
    print_password(ri + 1, rlength, rule, wi, wlength, pi + wlength);
  }
  else {
    for (int i = 0; i < 10; i++) {
      password[pi] = i + '0';
      password[pi + 1] = '\0';
      print_password(ri + 1, rlength, rule, wi, wlength, pi + 1);
    }
  }
}

int main()
{
  while (true) {
    int nr_words;
    if (scanf("%d\n", &nr_words) == EOF)
      break;
    for (int i = 0; i < nr_words; i++)
      gets(words[i]);
    int nr_rules;
    scanf("%d\n", &nr_rules);
    printf("--\n");
    for (int ri = 0; ri < nr_rules; ri++) {
      char rule[nr_rule_chars_max];
      gets(rule);
      int rlength = strlen(rule);
      for (int wi = 0; wi < nr_words; wi++) {
        int wlength = strlen(words[wi]);
        print_password(0, rlength, rule, wi, wlength, 0);
      }
    }
  }
  return 0;
}