USACO1.2.3 Name That Number (namenum)

/*
ID:shijiey1
PROG:namenum
LANG:C++
*/
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>

using namespace std;

string dict[5000];
string num;
char letter[10][3] = {{},{}, {'A','B','C'}, {'D','E','F'}, {'G','H','I'}
, {'J','K','L'}, {'M','N','O'}, {'P','R','S'}, {'T','U','V'}, {'W','X','Y'}};
int n = 0;

bool contains(char c, int i) {
return letter[i][0] == c || letter[i][1] == c || letter[i][2] == c;
}

int main() {
freopen("namenum.out", "w", stdout);
freopen("namenum.in", "r", stdin);
cin >> num;
freopen("dict.txt", "r", stdin);
while (cin >> dict[n++]);
bool has = false;
for (int i = 0; i < n; i++) {
if (dict[i].size() != num.size()) continue;
bool flag = false;
for (int j = 0; j < num.size(); j++) {
if (!contains(dict[i][j], num[j] - '0')) {
flag = true;
break;
}
}
if (!flag) {
cout << dict[i] << endl;
has = true;
}
}
if (!has) {
printf("NONE\n");
}
return 0;
}