UVa 128 - Software CRC

128.cpp

#include <bits/stdc++.h>
using namespace std;

#define F first
#define S second
#define endl '\n'
#define PB push_back

typedef long long ll;
typedef vector<ll> vll;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<int> vi;

const int MOD = 34943;
const int oo = ~(1<<31);

void load(int c, int &num) {
    num <<= 8;
    num += c;
    num %= MOD;
}

string clean(int n) {
    string num;
    stringstream s;
    s << hex << n;
    num = s.str();

    while(num.size() < 4)
        num = "0" + num;

    for(char &c : num) c = toupper(c);
    num.insert(2, " ");

    return num;
}

int main() {
    #ifndef CBDAVIDES
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
    #endif

    int nm;
    string line;

    while(getline(cin, line) && line != "#") {

        int num = 0;
        for(char c : line)
            load(c, num);

        num = ((ll)num << 16) % MOD;
        cout << clean((MOD - num) % MOD) << endl;
    }
    return 0;
}