Submission #772862

#	Time	Username	Problem	Language	Result	Execution time	Memory
772862		fve5	Connecting Supertrees (IOI20_supertrees)	C++17	56 / 100	187 ms	28016 KiB

supertrees

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

struct DSU {
    vector<int> nodes;

    int find(int node) {
        if (nodes[node] < 0) return node;
        return nodes[node] = find(nodes[node]);
    }

    void join(int u, int v) {
        u = find(u), v = find(v);
        if (u == v) return;

        if (nodes[u] > nodes[v]) swap(u, v);
        nodes[u] += nodes[v];
        nodes[v] = u;
    }

    map<int, vector<int>> get_cc() {
        map<int, vector<int>> ans;
        for (int i = 0; i < nodes.size(); i++) {
            ans[find(i)].push_back(i);
        }
        return ans;
    }

    DSU(int size) : nodes(size, -1) { }
};

int construct(vector<vector<int>> p) {
    int n = p.size();
    
    vector adj(n, vector(n, 0));
    vector act_p(n, vector(n, 0));
    DSU dsu(n);
    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            if (p[i][j]) dsu.join(i, j);
        }
    }

    auto ccs = dsu.get_cc();
    for (auto [_, cc]: ccs) {
        DSU dsu2(cc.size());
        for (auto x: cc) {
            for (auto y: cc) {
                act_p[x][y] = 2;
            }
        }
        for (int i = 0; i < cc.size(); i++) {
            for (int j = 0; j < cc.size(); j++) {
                if (p[cc[i]][cc[j]] == 1) dsu2.join(i, j);
            }
        }
        auto ccs2 = dsu2.get_cc();
        vector<int> cycle;
        for (auto [r, cc2]: ccs2) {
            for (auto x: cc2) {
                for (auto y: cc2) {
                    act_p[cc[x]][cc[y]] = 1;
                }
            }
            cycle.push_back(cc[r]);
            for (int i = 1; i < cc2.size(); i++) {
                adj[cc[cc2[i]]][cc[cc2[i - 1]]] = adj[cc[cc2[i - 1]]][cc[cc2[i]]] = 1;
            }
        }
        if (cycle.size() < 3) continue;
        for (int i = 0; i < cycle.size(); i++) {
            adj[cycle[i]][cycle[(i + 1) % cycle.size()]] = adj[cycle[(i + 1) % cycle.size()]][cycle[i]] = 1;
        }
    }
    if (p == act_p) {
        build(adj);
        return 1;
    } else {
        return 0;
    }
}

Compilation message (stderr)

supertrees.cpp: In member function 'std::map<int, std::vector<int> > DSU::get_cc()':
supertrees.cpp:24:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |         for (int i = 0; i < nodes.size(); i++) {
      |                         ~~^~~~~~~~~~~~~~
supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:53:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |         for (int i = 0; i < cc.size(); i++) {
      |                         ~~^~~~~~~~~~~
supertrees.cpp:54:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |             for (int j = 0; j < cc.size(); j++) {
      |                             ~~^~~~~~~~~~~
supertrees.cpp:67:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |             for (int i = 1; i < cc2.size(); i++) {
      |                             ~~^~~~~~~~~~~~
supertrees.cpp:72:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |         for (int i = 0; i < cycle.size(); i++) {
      |                         ~~^~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 10 / 10
• Subtask 3: 0 / 19
• Subtask 4: 35 / 35
• Subtask 5: 0 / 21
• Subtask 6: 0 / 4