Submission #1066146

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066146		kkkkkkkk	Connecting Supertrees (IOI20_supertrees)	C++14	46 / 100	123 ms	24148 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>

using namespace std;

int parent[1005], sz[1005], parent2[1005], sz2[1005];

int Find(int x) {
    if (x==parent[x])
        return x;
    return parent[x]=Find(parent[x]);
}

int Find2(int x) {
    if (x==parent2[x])
        return x;
    return parent2[x]=Find2(parent2[x]);
}

void Union(int a, int b) {
    a=Find(a), b=Find(b);
    if (a==b) return;
    if (sz[a]<sz[b])
        swap(a, b);
    sz[a]+=sz[b];
    parent[b]=a;
}

void Union2(int a, int b) {
    a=Find2(a), b=Find2(b);
    if (a==b) return;
    if (sz2[a]<sz2[b])
        swap(a, b);
    sz2[a]+=sz2[b];
    parent2[b]=a;
}

int construct(vector<vector<int> > paths) {
    int n=paths.size();
    vector<vector<int> > a(n, vector<int> (n, 0));
    for (int i=0;i<n;i++)
        sz[i]=1, parent[i]=i, sz2[i]=1, parent2[i]=i;
    for (int i=0;i<n;i++)
        for (int j=i+1;j<n;j++)
            if (paths[i][j]) Union(i, j);
    vector<int> gr[n];
    for (int i=0;i<n;i++) {
        int lider=Find(i);
        gr[lider].push_back(i);
    }
    for (int i=0;i<n;i++) {
        if (!gr[i].size()) continue;
        vector<int> roots;
        for (int j=0;j<gr[i].size();j++) {
            int x=gr[i][j];
            for (int k=j+1;k<gr[i].size();k++) {
                int y=gr[i][k];
                if (paths[x][y]==1) Union2(x, y);
            }
        }
        for (auto x:gr[i]) {
            if (Find2(x)==x) roots.push_back(x);
            else a[x][parent2[x]]=1, a[parent2[x]][x]=1;
        }
        if (roots.size()<=1) continue;
        if (roots.size()==2) return 0;
        int x=roots[0], y=roots[roots.size()-1];
        for (int j=0;j<roots.size()-1;j++)
            a[roots[j]][roots[j+1]]=1, a[roots[j+1]][roots[j]]=1;
        a[x][y]=1, a[y][x]=1;
    }
    build(a);
    return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:54:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |         for (int j=0;j<gr[i].size();j++) {
      |                      ~^~~~~~~~~~~~~
supertrees.cpp:56:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |             for (int k=j+1;k<gr[i].size();k++) {
      |                            ~^~~~~~~~~~~~~
supertrees.cpp:68:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |         for (int j=0;j<roots.size()-1;j++)
      |                      ~^~~~~~~~~~~~~~~

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