Submission #451362

#	Time	Username	Problem	Language	Result	Execution time	Memory
451362		prvocislo	Flood (IOI07_flood)	C++17	100 / 100	292 ms	31152 KiB

flood

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
typedef long long ll;
using namespace std;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin >> n;
    vector<int> x(n), y(n);
    for (int i = 0; i < n; i++) cin >> x[i] >> y[i];
    cin >> m;
    vector<int> a(m), b(m);
    vector<vector<bool> > vis1(m, vector<bool>(2, false));
    vector<bool> vis2(m, false);
    vector<vector<int> > g(n, vector<int>(4, -1));
    set<pair<pair<int, int>, int>> pq;
    for (int i = 0; i < m; i++)
    {
        cin >> a[i] >> b[i]; a[i]--, b[i]--;
        if (x[b[i]] < x[a[i]] || y[b[i]] < y[a[i]]) swap(a[i], b[i]);
        if (y[a[i]] == y[b[i]])
        {
            g[a[i]][0] = i;
            g[b[i]][2] = i;
        }
        if (x[a[i]] == x[b[i]])
        {
            g[a[i]][3] = i;
            g[b[i]][1] = i;
        }
        pq.insert({ {-x[b[i]], y[b[i]]}, i });
    }
    while (!pq.empty())
    {
        int i = pq.begin()->second;
        pq.erase(pq.begin());
        if (vis2[i]) continue;
        //cout << "\n";
        int u = a[i], d = find(g[b[i]].begin(), g[b[i]].end(), i) - g[b[i]].begin();
        vector<int> nw;
        while (true)
        {
            int e = -1, d2 = -1;
            for (int i = 3; i < 7; i++)
            {
                e = g[u][(d + i) % 4];
                if (e != -1 && !vis2[e])
                {
                    d2 = (d + i) % 4;
                    break;
                }
            }
            bool flag = a[e] == u;
            if (vis1[e][flag]) break;
            vis1[e][flag] = true;
            nw.push_back(e);
            u = u ^ a[e] ^ b[e], d = d2;
            //cout << e << "\n";
        }
        for (int e : nw) vis2[e] = true;
    }
    vector<int> ans;
    for (int i = 0; i < m; i++) if (vis1[i][0] && vis1[i][1])
        ans.push_back(i);
    cout << ans.size() << "\n";
    for (int i : ans) cout << i + 1 << "\n";
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 3 / 3
• Subtask 5: 10 / 10
• Subtask 6: 3 / 3
• Subtask 7: 3 / 3
• Subtask 8: 3 / 3
• Subtask 9: 3 / 3
• Subtask 10: 9 / 9
• Subtask 11: 9 / 9
• Subtask 12: 9 / 9
• Subtask 13: 9 / 9
• Subtask 14: 9 / 9