Submission #1073590

#	Time	Username	Problem	Language	Result	Execution time	Memory
1073590		blushingecchigirl	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	140 ms	24184 KiB

supertrees

#include <bits/stdc++.h>
using namespace std;
#define pb push_back

struct dsu {
    vector<int> parent, rank;
    int size;

    dsu(int sz) {
        size = sz;
        rank.assign(size, 1);
        parent.resize(size);
        for(int i = 0; i<size; i++) parent[i] = i;
    }
    int search(int v) {
        if(v == parent[v]) return v;
        return parent[v] = search(parent[v]);
    }
    void connect(int v, int u) {
        v = search(v);
        u = search(u);
        if(v == u) return;
        if(rank[v]>=rank[u]) parent[u] = v;
        else parent[v] = u;
        if(rank[v] == rank[u]) rank[v]++;
        return;
    }
};

void build(std::vector<std::vector<int>> b);
int construct(std::vector<std::vector<int>> p) {
	int n = p.size();
	bool ctr = 1;
    vector<vector<int>> b(n);
    for(int i = 0; i<n; i++) b[i].resize(n, 0);
    
    vector<int> a[n];
    dsu d = dsu(n);
    for(int i = 0; i<n; i++) {
        for(int j = 0; j<n; j++) {
            if(p[i][j]) d.connect(i, j);
        }
    }
    for(int i = 0; i<n; i++) {
        a[d.search(i)].pb(i);
    }
    for(int i = 0; i<n; i++) {
        int sz = a[i].size();
        for(int ii = 0; ii<sz; ii++) {
            for(int j = 0; j<sz; j++) {
                if(p[a[i][ii]][a[i][j]] == 0 || p[a[i][ii]][a[i][j]] == 3) ctr = 0;
            }
        }
        if(sz<=1) continue;
        vector<int> tree[sz], circle;
        dsu dd = dsu(sz);
        for(int ii = 0; ii<sz; ii++) {
            for(int j = 0; j<sz; j++) {
                if(p[a[i][ii]][a[i][j]] == 1) dd.connect(ii, j);
            }
        }
        for(int ii = 0; ii<sz; ii++) {
            tree[dd.search(ii)].pb(a[i][ii]);
        }
        for(int ii = 0; ii<sz; ii++) {
            if(tree[ii].size() == 0) continue;
            if(tree[ii].size()>1) {
                for(size_t j = 1; j<tree[ii].size(); j++) b[tree[ii][j]][tree[ii][j-1]] = b[tree[ii][j-1]][tree[ii][j]] = 1;
            }
            for(size_t iii = 0; iii < tree[ii].size(); iii++) {
                for(size_t j = 0; j < tree[ii].size(); j++) {
                    if(p[tree[ii][iii]][tree[ii][j]] != 1) ctr = 0;
                }
            }
            circle.pb(tree[ii][0]);
        }
        for(size_t ii = 1; ii<circle.size(); ii++) {
            b[circle[ii]][circle[ii-1]] = b[circle[ii-1]][circle[ii]] = 1;
        }
        if(circle.size()>1) b[circle[0]][circle.back()] = b[circle.back()][circle[0]] = 1;
        if(circle.size() == 2) ctr = 0;
    }
	if(ctr) build(b);
	return ctr;
}

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