Submission #769103

#	Time	Username	Problem	Language	Result	Execution time	Memory
769103		t6twotwo	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	165 ms	22076 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>
using namespace std;
int construct(std::vector<std::vector<int>> a) {
    int N = a.size();
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            if (a[i][j] == 3) {
                return 0;
            }
        }
    }
    vector<bool> vis(N);
    auto bfs = [&](int s, int t) {
        vector<int> v;
        queue<int> q;
        q.push(s);
        vis[s] = 1;
        while (!q.empty()) {
            int x = q.front();
            q.pop();
            v.push_back(x);
            for (int y = 0; y < N; y++) {
                if (!vis[y] && a[x][y] == t) {
                    vis[y] = 1;
                    q.push(y);
                }
            }
        }
        return v;
    };
    vector ans(N, vector<int>(N));
    for (int i = 0; i < N; i++) {
        if (vis[i]) {
            continue;
        }
        auto v = bfs(i, 1);
        for (int x : v) {
            for (int j = 0; j < N; j++) {
                if (a[x][j] != a[v[0]][j]) {
                    return 0;
                }
            }
        }
        for (int j = 1; j < v.size(); j++) {
            ans[i][v[j]] = ans[v[j]][i] = 1;
        }
        vis[i] = 0;
    }
    for (int i = 0; i < N; i++) {
        if (vis[i]) {
            continue;
        }
        auto v = bfs(i, 2);
        if (v.size() == 1) {
            continue;
        }
        if (v.size() == 2) {
            return 0;
        }
        for (int j = 0; j < v.size(); j++) {
            for (int k = j + 1; k < v.size(); k++) {
                if (!a[v[j]][v[k]]) {
                    return 0;
                }
            }
        }
        for (int j = 0; j < v.size(); j++) {
            int x = v[j];
            int y = v[j + 1 == v.size() ? 0 : j + 1];
            ans[x][y] = ans[y][x] = 1;
        }
    }
    build(ans);
    return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:45:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |         for (int j = 1; j < v.size(); j++) {
      |                         ~~^~~~~~~~~~
supertrees.cpp:61:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |         for (int j = 0; j < v.size(); j++) {
      |                         ~~^~~~~~~~~~
supertrees.cpp:62:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |             for (int k = j + 1; k < v.size(); k++) {
      |                                 ~~^~~~~~~~~~
supertrees.cpp:68:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |         for (int j = 0; j < v.size(); j++) {
      |                         ~~^~~~~~~~~~
supertrees.cpp:70:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   70 |             int y = v[j + 1 == v.size() ? 0 : j + 1];
      |                       ~~~~~~^~~~~~~~~~~

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