Submission #1073411

#	Time	Username	Problem	Language	Result	Execution time	Memory
1073411		blushingecchigirl	Connecting Supertrees (IOI20_supertrees)	C++17	40 / 100	184 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++) {
        if(a[i].size()<=1) continue;
        int pth = p[a[i][0]][a[i][1]];
        for(int ii:a[i]) {
            for(int j:a[i]) {
                if(ii == j) continue;
                if(p[ii][j] != pth) ctr = 0;
            }
        }
        for(int ii = 1; ii<a[i].size(); ii++) {
            b[a[i][ii]][a[i][ii-1]] = b[a[i][ii-1]][a[i][ii]] = 1;
        }
        if(pth == 2) b[a[i][0]][a[i].back()] = b[a[i].back()][a[i][0]] = 1;
        if(pth == 2 && a[i].size() == 2) ctr = 0;
    }
	if(ctr) build(b);
	return ctr;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:56:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |         for(int ii = 1; ii<a[i].size(); ii++) {
      |                         ~~^~~~~~~~~~~~

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