Submission #655082

#	Time	Username	Problem	Language	Result	Execution time	Memory
655082		benjaminkleyn	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	191 ms	22208 KiB

supertrees

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

int par[1000];

int find(int u)
{
    if (par[u] == u)
        return u;
    return par[u] = find(par[u]);
}

void unite(int u, int v)
{
    u = find(u), v = find(v);
    par[v] = u;
}

vector<int> comp[1000];

int construct(vector<vector<int>> p) {
	int n = p.size();

    iota(par, par + n, 0);

    for (int i = 0; i < n; i++)
        for (int j = 0; j < n; j++)
        {
            if (p[i][j] > 0)
                unite(i, j);
            if (p[i][j] == 3)
                return 0;
        }

    for (int i = 0; i < n; i++)
        comp[find(i)].push_back(i);

	vector<vector<int>> answer(n, vector<int>(n));
    for (int k = 0; k < n; k++)
        if (find(k) == k && comp[k].size() >= 2)
        {
            vector<set<int>> trees;
            vector<int> cycle;
            vector<bool> done(n);
            for (int i : comp[k])
            {
                if (done[i]) continue;
                done[i] = true;

                set<int> tree;
                tree.insert(i);
                for (int j : comp[k]) 
                    if (p[i][j] == 1 && !done[j])
                    {
                        done[j] = true;
                        answer[i][j] = 1;
                        answer[j][i] = 1;
                        tree.insert(j);
                    }
                trees.push_back(tree);
                cycle.push_back(i);
            }

            for (set<int> tree : trees)
                for (int i : tree)
                {
                    for (int j : comp[k]) 
                        if (tree.find(j) == tree.end() && p[i][j] != 2)
                            return 0;

                    for (int j : tree)
                        if (p[i][j] != 1)
                            return 0;
                }

            for (int i : cycle)
                for (int j : cycle)
                    if (i != j && p[i][j] != 2)
                        return 0;

            if (cycle.size() == 2) 
                return 0;
            if (cycle.size() == 1)
                continue;

            cycle.push_back(comp[k][0]);

            for (int i = 0; i < cycle.size() - 1; i++)
            {
                answer[cycle[i]][cycle[i+1]] = 1;
                answer[cycle[i+1]][cycle[i]] = 1;
            }
        }

    build(answer);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:37:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   37 |     for (int i = 0; i < n; i++)
      |     ^~~
supertrees.cpp:40:2: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   40 |  vector<vector<int>> answer(n, vector<int>(n));
      |  ^~~~~~
supertrees.cpp:90:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   90 |             for (int i = 0; i < cycle.size() - 1; 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