Submission #576164

#	Time	Username	Problem	Language	Result	Execution time	Memory
576164		MadokaMagicaFan	Carnival Tickets (IOI20_tickets)	C++14	11 / 100	2 ms	1492 KiB

tickets

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using vi = vector<int>;
using pi = pair<int,int>;

#define all(v)          v.begin(),v.end()
#define sort(v)         sort(all(v))
#define endl            '\n'
#define forn(i,n)       for(int i = 0; i < n; ++i)
#define forbe(i,b,e)    for(int i = b; i < e; ++i)
#define forr(i,n)       for(int i = n-1; i >= 0; --i)
#define sz(v)           ((int)v.size())
#define pb              push_back
#define f               first
#define s               second

const int N = 1500;
const int M = 1500;

void allocate_tickets(vector<vi>s);

ll subtask1(int k, vector<vi> &x) {
    int n = sz(x);
    int m = sz(x[0]);
    vector<vi> s(n);
    forn(i,n) s[i].assign(m,0);

    vi ans;

    forn(i,n) {
        ans.pb(x[i][0]);
    }

    sort(ans);
    
    ll rans = 0;

    forn(i,n) {
        if (i < (n>>1))
            rans -= ans[i];
        else
            rans += ans[i];
    }

    forn(i,n) {
        s[i][0] = 0;
    }

    allocate_tickets(s);

    return rans;
}

ll subtask4(int k, vector<vi> &x) {
    int n = sz(x);
    int m = sz(x[0]);
    vector<vi> s(n);
    forn(i,n) s[i].assign(m,0);
    vector<pi> vals;
    vector<vector<pi>> sval(n);

    int topp[N];
    int botp[N];

    forn(i,n) {
        topp[i] = n-1;
        botp[i] = 0;
        forn(j,m) {
            sval[i].pb({x[i][j], j});
            vals.pb({x[i][j],i * m + j});
        }
        sort(sval[i]);
    }

    ll ans = 0;
    sort(vals);
    bitset<N*M> c;
    bitset<N*M> mid;

    int midval = vals[((n*m)>>1)].f;
    forn(i,n*m) {
        ans -= (ll)vals[i].f;
        if (vals[i].f == midval)
            mid[i] = 1;
        if (i < ((n*m)>>1)) continue;
        c[vals[i].s] = 1;
        ans += (ll)vals[i].f;
        ans += (ll)vals[i].f;
    }

    bitset<N> up;
    int cnt;
    forn(j, k) {
        forn(i,n) up[i] = 0;
        cnt = 0;
        forn(i,n) {
            if (cnt == (n>>1))
                break;
            if (c[ i*m + sval[i][topp[i]].s ] == 0) continue;
            ++cnt;
            up[i]=1;
        }

        forn(i,n) {
            if (cnt == (n>>1))
                break;
            if (up[i]) continue;
            if (mid[ i*m + sval[i][topp[i]].s ] == 0) continue;
            ++cnt;
            up[i]=1;
        }

        assert(cnt == (n>>1));

        forn(i,n) {
            if (up[i]) {
                s[i][ sval[i][topp[i]].s ] = j;
                --topp[i];
            } else {
                s[i][ sval[i][botp[i]].s ] = j;
                ++botp[i];
            }
        }
    }

    allocate_tickets(s);

    return ans;
}


ll find_maximum(int k, vector<vi>x) {
    int n = sz(x);
    int m = sz(x[0]);
    if (m == 1) return subtask1(k,x);
    if (m == k) return subtask4(k,x);

    return 0;
}

#ifdef ONPC
void allocate_tickets(vector<vi>s) {
    forn(i, sz(s)) {
        forn(j, sz(s[0])) {
            cout << s[i][j] << ' ';
        }
        cout << endl;
    }
}

void solve() {
    int n, m, k;
    cin >> n >> m >> k;
    vector<vi> x(n);
    forn(i,n) {
        x[i].assign(m,0);
    }

    forn(j,m) {
        forn(i,n) {
            cin >> x[i][j];
        }
    }

    cout << find_maximum(k, x) << endl;
}

int main() {
    freopen("in", "r", stdin);
//    ios_base::sync_with_stdio(0);cin.tie(0);
    solve();
}
#endif

Compilation message (stderr)

tickets.cpp: In function 'll find_maximum(int, std::vector<std::vector<int> >)':
tickets.cpp:136:9: warning: unused variable 'n' [-Wunused-variable]
  136 |     int n = sz(x);
      |         ^

• Subtask 1: 11 / 11
• Subtask 2: 0 / 16
• Subtask 3: 0 / 14
• Subtask 4: 0 / 14
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23
• Subtask 7: 0 / 10