Submission #1046542

#	Time	Username	Problem	Language	Result	Execution time	Memory
1046542		vanea	Connecting Supertrees (IOI20_supertrees)	C++14	100 / 100	122 ms	22352 KiB

supertrees

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

const int mxN = 1e3+10;

vector<int> adj[mxN];

int p[mxN], root[mxN];

int get(int x) {
    return p[x] < 0 ? x : p[x] = get(p[x]);
}

void uni(int x, int y) {
    x = get(x); y = get(y);
    if(x == y) return ;
    if(p[x] > p[y]) swap(x, y);
    p[x] += p[y];
    p[y] = x;
}

bool same(int a, int b) {
    return get(a) == get(b);
}

int construct(vector<vector<int>> P) {
    int n = P.size();
    for(int i = 0; i < n; i++) {
        p[i] = -1;
        root[i] = i;
    }
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < n; j++) {
            if(P[i][j] == 3) return 0;
            if(P[i][j] == 1 && !same(i, j)) {
                adj[i].push_back(j);
                adj[j].push_back(i);
                uni(i, j);
            }
        }
    }
    bool pos = true;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < n; j++) {
            if(P[i][j] == 1 && !same(i, j)) pos = false;
            else if(P[i][j] == 2 && same(i, j)) pos = false;
            else if(!P[i][j] && same(i, j)) pos = false;
        }
    }
    for(int i = 0; i < n; i++) {
        set<int> s;
        for(int j = 0; j < n; j++) {
            if(P[i][j] == 2 && !same(i, j)) {
                s.insert(get(j));
            }
        }
        if(s.empty()) continue;
        if(s.size() == 1) {
            pos = false;
            break;
        }
        vector<int> v; for(auto it : s) v.push_back(it);
        for(int i = 0; i+1 < v.size(); i++) {
            int a = root[get(v[i])], b = root[get(v[i+1])];
            adj[a].push_back(b);
            adj[b].push_back(a);
        }
        int x = root[get(i)];
        adj[x].push_back(root[v[0]]);
        adj[root[v[0]]].push_back(x);
        adj[x].push_back(root[v.back()]);
        adj[v.back()].push_back(x);
        for(int i = 0; i < v.size(); i++) {
            uni(x, v[i]);
        }
    }
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < n; j++) {
            if(!P[i][j] && same(i, j)) pos = false;
        }
    }
    if(!pos) return 0;
    vector<vector<int>> ans(n, vector<int>(n));
    for(int i = 0; i < n; i++) {
        for(auto it : adj[i]) {
            ans[i][it] = ans[it][i] = 1;
        }
    }
    build(ans);
    return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:65:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |         for(int i = 0; i+1 < v.size(); i++) {
      |                        ~~~~^~~~~~~~~~
supertrees.cpp:75:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   75 |         for(int i = 0; i < v.size(); i++) {
      |                        ~~^~~~~~~~~~

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