Submission #619523

#	Time	Username	Problem	Language	Result	Execution time	Memory
619523		sokratisi	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	281 ms	28164 KiB

supertrees

#include "supertrees.h"
#include <vector>
#include <unordered_set>
#include <unordered_map>

using namespace std;

vector<vector<int>> groups;
int n;
vector<vector<int>> adj;
vector<bool> vis;
int total;
unordered_map<int, int> group;

// void build(vector<vector<int>> answer) {
//     for (int i = 0; i < answer.size(); i++) {
//         for (int j = 0; j < answer.size(); j++) {
//             printf("%d ", answer[i][j]);
//         }
//         printf("\n");
//     }
// }

void dfs(int s) {
    vis[s] = true;
    groups[groups.size() - 1].push_back(s);
    group[s] = groups.size() - 1;
    for (auto u: adj[s]) {
        total++;
        if (!vis[u]) {
            dfs(u);
        }
    }
}

int construct(vector<vector<int>> p) {
	n = p.size();
    adj.resize(n);
    vis.resize(n, false);
    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            if (p[i][j] == 1) {
                adj[i].push_back(j);
                adj[j].push_back(i);
            }
        }
    }
    vector<int> pb;
    bool ok = true;
    for (int i = 0; i < n; i++) {
        if (!vis[i]) {
            total = 0;
            groups.push_back(pb);
            dfs(i);
            int t = groups[groups.size() - 1].size();
            if (t * (t - 1) != total) ok = false;
        }
    }
    if (!ok) return 0;

    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            if (p[i][j] == 2) {
                adj[i].push_back(j);
                adj[j].push_back(i);
            }
        }
    }
    unordered_set<int> rep;
    for (auto u: groups) {
        rep.insert(u[0]);
    }
    vector<vector<int>> concomp;
    for (int i = 0; i < n; i++) vis[i] = false;
    for (auto u: groups) {
        if (!vis[u[0]]) {
            vis[u[0]] = true;
            concomp.push_back(pb);
            concomp[concomp.size() - 1].push_back(u[0]);
            for (auto v: adj[u[0]]) {
                if (!vis[v]) {
                    if (rep.find(v) != rep.end()) concomp[concomp.size() - 1].push_back(v);
                    vis[v] = true;
                }
            }
        }
    }
    ok = true;
    for (int i = 0; i < concomp.size(); i++) {
        if (concomp[i].size() == 2) ok = false;
    }
    for (int i = 0; i < concomp.size(); i++) {
        unordered_set<int> curcomp;
        for (int j = 0; j < concomp[i].size(); j++) {
            for (auto u: groups[group[concomp[i][j]]]) {
                curcomp.insert(u);
            }
        }
        for (auto u: curcomp) {
            for (int i = 0; i < n; i++) {
                if (curcomp.find(i) != curcomp.end()) if (p[u][i] == 0) ok = false;
                if (curcomp.find(i) == curcomp.end()) if (p[u][i] != 0) ok = false;
            }
        }
    }
    if (!ok) {
        // printf("first\n");
        return 0;
    }

	vector<vector<int>> answer(n, vector<int>(n, 0));
	for (int i = 0; i < groups.size(); i++) {
        for (int j = 1; j < groups[i].size(); j++) {
            answer[groups[i][0]][groups[i][j]] = 1;
            answer[groups[i][j]][groups[i][0]] = 1;
        }
    }
    for (int i = 0; i < concomp.size(); i++) {
        if (concomp[i].size() != 1) {
            for (int j = 0; j < concomp[i].size() - 1; j++) {
                answer[concomp[i][j]][concomp[i][j+1]] = 1;
                answer[concomp[i][j+1]][concomp[i][j]] = 1;
            }
            answer[concomp[i][concomp[i].size() - 1]][concomp[i][0]] = 1;
            answer[concomp[i][0]][concomp[i][concomp[i].size() - 1]] = 1;
        }
    }

	build(answer);
	return 1;
}

// int main() {
//     int n;
//     scanf("%d", &n);
//     vector<vector<int>> p(n, vector<int>(n));
//     for (int i = 0; i < n; i++) {
//         for (int j = 0; j < n; j++) {
//             scanf("%d", &p[i][j]);
//         }
//     }
//     printf("Return value: %d\n", construct(p));
//     return 0;
// }

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:89:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   89 |     for (int i = 0; i < concomp.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~~
supertrees.cpp:92:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |     for (int i = 0; i < concomp.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~~
supertrees.cpp:94:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   94 |         for (int j = 0; j < concomp[i].size(); j++) {
      |                         ~~^~~~~~~~~~~~~~~~~~~
supertrees.cpp:112:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  112 |  for (int i = 0; i < groups.size(); i++) {
      |                  ~~^~~~~~~~~~~~~~~
supertrees.cpp:113:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  113 |         for (int j = 1; j < groups[i].size(); j++) {
      |                         ~~^~~~~~~~~~~~~~~~~~
supertrees.cpp:118:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  118 |     for (int i = 0; i < concomp.size(); i++) {
      |                     ~~^~~~~~~~~~~~~~~~
supertrees.cpp:120:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  120 |             for (int j = 0; j < concomp[i].size() - 1; j++) {
      |                             ~~^~~~~~~~~~~~~~~~~~~~~~~

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