Submission #1007396

#	Time	Username	Problem	Language	Result	Execution time	Memory
1007396		Ahmed57	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	138 ms	22224 KiB

supertrees

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

using namespace std;
int pr[100001];
int find(int x){
    if(x==pr[x])return x;
    return pr[x] = find(pr[x]);
}
void mergegroup(int a,int b){
    a = find(a);
    b = find(b);
    if(a==b)return ;
    pr[a] = b;
}
int pr2[100001];
int find2(int x){
    if(x==pr2[x])return x;
    return pr2[x] = find2(pr2[x]);
}
void mergegroup2(int a,int b){
    a = find2(a);
    b = find2(b);
    if(a==b)return ;
    pr2[a] = b;
}
int construct(vector<vector<int>> p){
    int n = p.size();
    vector<vector<int>> B;
    vector<int> x(n,0);
    for(int i = 0;i<n;i++){
        B.push_back(x);
    }
    //phase 1
    for(int i = 0;i<n;i++){
        pr[i] = i;
    }
    for(int i = 0;i<n;i++){
        for(int j = 0;j<n;j++){
            if(p[i][j]==3){
                return 0;
            }
            if(i==j)continue;
            if(p[i][j]){
                mergegroup(i,j);
            }
        }
    }
    for(int i = 0;i<n;i++){
        for(int j = 0;j<n;j++){
            if(i==j)continue;
            if(find(i)==find(j)){
                if(p[i][j]==0){
                    return 0;
                }
            }else{
                if(p[i][j]){
                    return 0;
                }
            }
        }
    }
    //phase 2
    for(int i = 0;i<n;i++){
        pr2[i] = i;
    }
    for(int i = 0;i<n;i++){
        for(int j = 0;j<n;j++){
            if(i==j)continue;
            if(p[i][j]==1){
                mergegroup2(i,j);
            }
        }
    }
    for(int i = 0;i<n;i++){
        for(int j = 0;j<n;j++){
            if(i==j)continue;
            if(find2(i)==find2(j)){
                if(p[i][j]!=1){
                    return 0;
                }
            }else{
                if(p[i][j]==1){
                    return 0;
                }
            }
        }
    }
    for(int i = 0;i<n;i++){
        if(i==find(i)){
            vector<int> lol;
            for(int j = 0;j<n;j++){
                if(find(i)==find(j)){
                    lol.push_back(j);
                }
            }
            vector<int> ror[n];
            for(int j:lol){
                ror[find2(j)].push_back(j);
            }
            vector<int> nah;
            for(int j = 0;j<n;j++){
                if(ror[j].size()){
                    nah.push_back(j);
                }
                for(int e = 1;e<ror[j].size();e++){
                    B[ror[j][e-1]][ror[j][e]]=1;
                    B[ror[j][e]][ror[j][e-1]]=1;
                }
            }
            if(nah.size()==2){
                return 0;
            }
            for(int j = 0;j<nah.size();j++){
                int a = nah[j] , b = nah[(j+1)%nah.size()];
                B[a][b] = 1;
                B[b][a] = 1;
            }
        }
    }
    for(int i = 0;i<n;i++)B[i][i] = 0;
    build(B);
    return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:106:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  106 |                 for(int e = 1;e<ror[j].size();e++){
      |                               ~^~~~~~~~~~~~~~
supertrees.cpp:114:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  114 |             for(int j = 0;j<nah.size();j++){
      |                           ~^~~~~~~~~~~

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