Submission #1311836

#	Time	Username	Problem	Language	Result	Execution time	Memory
1311836		michael12	Connecting Supertrees (IOI20_supertrees)	C++20	0 / 100	100 ms	22204 KiB

supertrees

#include "supertrees.h"
#include<bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
using namespace std;
const int maxn = 1e3 + 10;
vector<int> cnt[maxn];
struct DSU {
    vector<int> pt, sz;
    DSU(int sz0) {
        pt.resize(sz0);
        sz.resize(sz0, 1);
        for (int i = 0; i < sz0; i++) pt[i] = i;
    }
    int find(int x) {
        if (x == pt[x]) return x;
        return pt[x] = find(pt[x]);
    }
    void unite(int u, int v) {
        int a = find(u), b = find(v);
        if (a != b) {
            if (sz[a] < sz[b]) swap(a, b);
            pt[b] = a;
            sz[a] += sz[b];
            for (auto x : cnt[b]) cnt[a].push_back(x);
            cnt[b].clear();
        }
    }
    bool smcomp(int u, int v) {
        return find(u) == find(v);
    }
};

int construct(vector<vector<int>> p) {
    int n = p.size();
    vector<vector<int>> T(n, vector<int>(n, 0));

    for (int i = 0; i < n; i++) cnt[i].clear(), cnt[i].push_back(i);
    DSU dsu(n);
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (p[i][j] == 1 && dsu.find(i) != dsu.find(j)) {
                dsu.unite(i, j);
                T[i][j] = T[j][i] = 1;
            }
        }
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (p[i][j] != 1 && dsu.find(i) == dsu.find(j)){
                return 0;
            }
        }
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (p[i][j] == 3 || (p[i][j] == 0 && dsu.find(i) == dsu.find(j))){
                return 0;
            }
        }
    }

    for (int i = 0; i < n; i++){
        cnt[i].clear();
    }
    for (int i = 0; i < n; i++){
        cnt[dsu.find(i)].push_back(i);
    }

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (p[i][j] == 2 && dsu.find(i) != dsu.find(j)){
                dsu.unite(i, j);
            }
        }
    }
    for (int i = 0; i < n; i++) {
        if (cnt[i].size() < 2) continue;
        if (cnt[i].size() == 2) return 0; 
        for (int j = 0; j < (int)cnt[i].size(); j++) {
            int u = cnt[i][j];
            int v = cnt[i][(j + 1) % cnt[i].size()];
            T[u][v] = T[v][u] = 1;
        }
    }

    build(T);
    return 1;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 10
• Subtask 3: 0 / 19
• Subtask 4: 0 / 35
• Subtask 5: 0 / 21
• Subtask 6: 0 / 4