Submission #1235082

#	Time	Username	Problem	Language	Result	Execution time	Memory
1235082		badge881	Connecting Supertrees (IOI20_supertrees)	C++20	100 / 100	118 ms	22288 KiB

supertrees

#ifndef HOME
#include "supertrees.h"
#endif
#include <vector>
using namespace std;

class DSU
{
    vector<int> bosses, sz;

public:
    DSU(int n)
    {
        bosses.resize(n + 1);
        sz.resize(n + 1);
        for (int i = 0; i < n; i++)
            bosses[i] = i, sz[i] = 1;
    }
    int boss(int u)
    {
        return bosses[u] == u ? u : bosses[u] = boss(bosses[u]);
    }
    bool merge(int u, int v)
    {
        int ru = boss(u), rv = boss(v);
        if (ru == rv)
            return 0;
        if (sz[ru] > sz[rv])
            swap(sz[ru], sz[rv]);
        bosses[ru] = rv;
        sz[rv] += sz[ru];
        return 1;
    }
};

int construct(vector<vector<int>> p)
{
    int n = p[0].size();
    vector<vector<int>> v(n, vector<int>(n, 0));
    DSU ufd1(n), ufd2(n);
    for (int i = 0; i < n; i++)
        for (int j = i + 1; j < n; j++)
            if (p[i][j] != 0)
                ufd1.merge(i, j);

    for (int i = 0; i < n; i++)
        for (int j = 0; j < n; j++)
            if (p[i][j] == 0 && ufd1.boss(i) == ufd1.boss(j))
                return 0;
            else if (p[i][j] == 1)
                ufd2.merge(i, j);
            else if (p[i][j] == 3)
                return 0;

    vector<vector<int>> comp(n), comp1(n);
    for (int i = 0; i < n; i++)
    {
        comp[ufd2.boss(i)].push_back(i);
        if (ufd2.boss(i) == i)
            comp1[ufd1.boss(i)].push_back(i);
    }
    for (int i = 0; i < n; i++)
        if (ufd2.boss(i) == i)
            for (int j = 1; j < comp[i].size(); j++)
                v[comp[i][j - 1]][comp[i][j]] = 
                v[comp[i][j]][comp[i][j - 1]] = 1;

    for (int i = 0; i < n; i++)
    {
        if (ufd1.boss(i) != i)
            continue;
        if (comp1[i].size() == 2)
            return 0;
        if (comp1[i].size() > 1)
        {
            for (int j = 0; j < comp1[i].size(); j++)
            {
                int u = comp1[i][j], v1 = comp1[i][(j + 1) % comp1[i].size()];
                v[u][v1] = v[v1][u] = 1;
            }
        }
    }
#ifndef HOME
    build(v);
#endif
    return 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