Submission #1038408

#	Time	Username	Problem	Language	Result	Execution time	Memory
1038408		Zicrus	Soccer Stadium (IOI23_soccer)	C++17	31 / 100	261 ms	47696 KiB

soccer

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

typedef long long ll;

ll tryCase(int n, vector<vector<int>> f) {
    vector<pair<ll, ll>> v(n, {-1, -1}), h(n, {-1, -1});
    ll num = 0;
    bool done = false;
    pair<ll, ll> prev = {-1, -1}, mn = {-1, -1};
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (!f[i][j]) {
                if (done)
                    return 0;
                if (v[i].first == -1) v[i].first = j;
                if (j - v[i].second > 1 && v[i].second != -1)
                    return 0;
                v[i].second = j;
                num++;
            }
        }
        if (v[i].first == -1 && num > 0) done = true;
        if (prev.first == -1) {
            prev = v[i];
            mn = v[i];
            continue;
        }
        if (v[i].first == -1) continue;
        if (v[i].first > mn.first && v[i].second > mn.second)
            return 0;
        if (v[i].first < mn.first && v[i].second < mn.second)
            return 0;
        mn.first = max(mn.first, v[i].first);
        mn.second = min(mn.second, v[i].second);
        if (v[i].first > prev.first && v[i].second > prev.second)
            return 0;
        if (v[i].first < prev.first && v[i].second < prev.second)
            return 0;
        prev = v[i];
    }

    if (num >= n*n-1) {
        ll x = -1, y = -1;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                if (f[i][j]) {
                    x = i;
                    y = j;
                }
            }
        }
    
        if (x == -1) return n*n;
        ll mx = max({
            x*n + y*n - x*y,
            (n-1-x)*n + y*n - (n-1-x)*y,
            x*n + (n-1-y)*n - x*(n-1-y),
            (n-1-x)*n + (n-1-y)*n - (n-1-x)*(n-1-y),
        });
        return mx;
    }

    num = 0;
    done = false;
    prev = {-1, -1};
    mn = {-1, -1};
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (!f[j][i]) {
                if (done)
                    return 0;
                if (h[i].first == -1) h[i].first = j;
                if (j - h[i].second > 1 && h[i].second != -1)
                    return 0;
                h[i].second = j;
                num++;
            }
        }
        if (h[i].first == -1 && num > 0) done = true;
        if (prev.first == -1) {
            prev = h[i];
            mn = h[i];
            continue;
        }
        if (h[i].first == -1) continue;
        if (h[i].first > mn.first && h[i].second > mn.second)
            return 0;
        if (h[i].first < mn.first && h[i].second < mn.second)
            return 0;
        mn.first = max(mn.first, h[i].first);
        mn.second = min(mn.second, h[i].second);
        if (h[i].first > prev.first && h[i].second > prev.second)
            return 0;
        if (h[i].first < prev.first && h[i].second < prev.second)
            return 0;
        prev = h[i];
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (h[i].first == -1 || h[j].first == -1) continue;
            if (h[i].first < h[j].first && h[i].second < h[j].second) return 0;
            if (h[i].first > h[j].first && h[i].second > h[j].second) return 0;
        }
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (v[i].first == -1 || v[j].first == -1) continue;
            if (v[i].first < v[j].first && v[i].second < v[j].second) return 0;
            if (v[i].first > v[j].first && v[i].second > v[j].second) return 0;
        }
    }

    return num;
}

int biggest_stadium(int n, vector<vector<int>> f) {
    if (n > 3) return tryCase(n, f);

    ll numCases = (1 << (n*n));
    ll res = 0;
    for (int i = 0; i < numCases; i++) {
        vector<vector<int>> c(n, vector<int>(n));
        ll val = 0;
        for (int x = 0; x < n; x++) {
            for (int y = 0; y < n; y++) {
                ll id = y*n + x;
                bool s = i & (1 << id);
                if (!s && f[x][y]) goto skip;
                c[x][y] = s;
            }
        }
        val = tryCase(n, c);
        skip:
        res = max(res, val);
    }
    return res;
}

• Subtask 0: 0 / 0
• Subtask 1: 1.5 / 6
• Subtask 2: 8 / 8
• Subtask 3: 5.5 / 22
• Subtask 4: 4.5 / 18
• Subtask 5: 4 / 16
• Subtask 6: 7.5 / 30