Submission #1070379

#	Time	Username	Problem	Language	Result	Execution time	Memory
1070379		vjudge1	Building 4 (JOI20_building4)	C++17	0 / 100	3 ms	604 KiB

building4

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int main() {
    ll n; cin >> n;
    ll ar[2*n], br[2*n];
    string s;

    for (ll i=0;i<2*n;i++) {
        cin >> ar[i];
        s+=".";
    }

    bool bisat[2*n];
    memset(bisat, true, sizeof(bisat));

    bool gagal = false;
    vector<ll>dt;
    vector<ll> lawan;
    ll na=0, nb=0, mn=0;
    for (ll i=0;i<2*n;i++) {
        cin >> br[i];
        bool ada = false;
        if (ar[i]<=br[i]) {
            if (ar[i]>=mn) {
                s[i]='A';
                na++;
                dt.push_back(ar[i]);
                lawan.push_back(br[i]);
                mn = ar[i];
            } else if (br[i]>=mn) {
                bisat[i]=false;
                s[i]='B';
                nb++;
                lawan.push_back(ar[i]);
                dt.push_back(br[i]);
                mn = br[i];
            } else {
                gagal = true;
            }
        } else {
            if (br[i]>=mn) {
                s[i]='B';
                nb++;
                lawan.push_back(ar[i]);
                dt.push_back(br[i]);
                mn = br[i];
            } else if (ar[i]>=mn) {
                bisat[i]=false;
                s[i]='A';
                na++;
                lawan.push_back(br[i]);
                dt.push_back(ar[i]);
                mn = ar[i];
            } else {
                gagal = true;
            }
        }
    }
    if (gagal) {
        cout << "-1" << endl;
        return 0;
    }

    ll beda = abs(na-nb);
    char car, balik;

    if (na>nb) {
        car = 'A';
        balik = 'B';
    } else if (nb>na) {
        car = 'B';
        balik = 'A';
    } else {
        cout << s << endl;
        return 0;
    }

    dt.push_back(1e11);

    for (int i=(2*n)-1;i>=0;i--) {
        if (!beda) break;
        if (s[i]==car) {
            if (bisat[i] && lawan[i]<=dt[i+1]) {
                beda-=2;
                s[i]= balik;
                dt[i] = lawan[i];
            }
        }
    }

    if (beda) {
        cout << "-1" << endl;
        return 0;
    }
    cout << s << endl;
    return 0;
}

Compilation message (stderr)

building4.cpp: In function 'int main()':
building4.cpp:25:14: warning: unused variable 'ada' [-Wunused-variable]
   25 |         bool ada = false;
      |              ^~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 89