UVa740 - Baudot Data Communication Code

#include <iostream>
#include <fstream>
#include <cstdio>
#include <string>

using namespace std;

const int N = 10000;

int conv(string &s);

int main()
{
    int state;
    string s[2];
    string message;
    string tmp;

#ifndef ONLINE_JUDGE
    ifstream cin("d:\\OJ\\uva_in.txt");
    //freopen("d:\\OJ\\uva_in.txt", "r", stdin);
#endif // ONLINE_JUDGE


    getline(cin, s[0]);
    getline(cin, s[1]);

    while (getline(cin, message)) {
        string ans;
        state = 0;
        if (message.length() % 5) {
            cout << endl;
            continue;
        }
        for (int i = 0; i < message.length(); i += 5) {
            tmp = message.substr(i, 5);
            //cout << "tmp:" << tmp << endl;

            if ((state == 1 && tmp == "11011") || (state == 0 && tmp == "11111")) {
                state = 1 - state;
                continue;
            }

            if (tmp == "11011" || tmp == "11111") continue;


            int num = conv(tmp);
            ans += s[state][num];
        }
        if (ans == "") cout << endl;
        else cout << ans << endl;
    }

    return 0;
}


int conv(string &s)
{
    int ans = 0;

    for (int i = 0; i < s.length(); i++) {
        ans = ans * 2 + (s[i] - '0');
    }

    return ans;
}