Submission #100318

#	Time	Username	Problem	Language	Result	Execution time	Memory
100318		ozneroL	Lun (COCI19_lun)	C++14	50 / 50	3 ms	384 KiB

lun

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

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


#define F first
#define S second

#define ERR 1e-9

#if !ONLINE_JUDGE && !EVAL
    #define dbg_var(x) cerr << #x << ": " << x << "\n";
    #define dbg_iter(x, y) cerr  << #x << ": " << print_iterable(x, y) << "\n";
#else
    #define dbg_var(x)
    #define dbg_iter(x, y)
#endif // ONLINE_JUDGE

template <typename T1, typename T2>
string print_iterable( T1 begin_iter, T2 end_iter){
    bool first = true;
    stringstream res;
    res << "[ ";
    for(; begin_iter != end_iter; ++begin_iter){
        if(!first) res << ", ";
        first = false;
        res << *begin_iter;
    }
    res << " ]";
    return res.str();
}

void aggMax(int & res, int x){ if(x > res)res = x; }
void aggMin(int & res, int x){ if(x < res)res = x; }

int II(){ int i; cin >> i; return i; }
void OI(int i){ cout << i; }

// constraints
#define MAXN 1000000

int sum(int n){
    int res = 0;
    while(n){
        res += n%10;
        n /= 10;
    }
    return res;
}

int lastStep(int sum, int mod){
    for(int i=0; i<=9; i++){
        if( (i*9+sum) % 10 == mod)
            return i;
    }
    /// value x in the sum
    return 0;
}

int findNumber(int xInTheSum){
    for(int i=0; i<=9; i++){
        if( sum(i*2) == xInTheSum)
            return i;
    }
    return 0;
}
#define sz(s) int(s.size())

int main() {
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    ios::sync_with_stdio(false);
    cin.tie(0);

    int N = II();

    string s;
    cin >> s;

    if(s[sz(s)-1] == 'x'){
        bool toDouble = true; int total_sum = 0;
        for(int i=sz(s)-2; i>=0; i--){

            if(toDouble) total_sum +=  sum( (s[i] - '0') * 2);
            else total_sum += (s[i] - '0');

            toDouble = !toDouble;
        }

        cout << (total_sum * 9) % 10 << "\n";
    }else{
        bool toDouble = true, xToDouble = false;
        int total_sum = 0;
        for(int i=sz(s)-2; i>=0; i--){
            if(s[i] == 'x'){
                xToDouble = toDouble;
                toDouble = !toDouble;
                continue;
            }
            if(toDouble) total_sum +=  sum( (s[i] - '0')*2);
            else total_sum += s[i] - '0';

            toDouble = !toDouble;
        }

        int xInTheSum = lastStep(total_sum*9, s[sz(s)-1] - '0');

        if(!xToDouble) cout << xInTheSum << "\n";
        else cout << findNumber(xInTheSum) << "\n";
    }

    return 0;
}

Compilation message (stderr)

lun.cpp: In function 'int main()':
lun.cpp:79:9: warning: unused variable 'N' [-Wunused-variable]
     int N = II();
         ^

• Subtask 1: 50 / 50