Submission #1011941

#	Time	Username	Problem	Language	Result	Execution time	Memory
1011941		LucaIlie	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	131 ms	22180 KiB

supertrees

#include "supertrees.h"
#include <vector>
#include <iostream>
using namespace std;
vector<vector<int>> answer;
#define nmax 1000
int daddy[nmax], daddy_cyc[nmax];
vector<int> cyc[nmax];

int find_daddy( int a ) {
    int x;
    if( daddy[a] == a )
        return a;
    x = find_daddy( daddy[a] );
    daddy[a] = x;
    return x;
}

void marry_daddy( int a, int b ) {
    int x, y;
    x = find_daddy( a );
    y = find_daddy( b );
    daddy[x] = y;
}

int find_daddy_cyc( int a ) {
    int x;
    if( daddy_cyc[a] == a )
        return a;
    x = find_daddy_cyc( daddy_cyc[a] );
    daddy_cyc[a] = x;
    return x;
}

void marry_daddy_cyc( int a, int b ) {
    int x, y;
    x = find_daddy_cyc( a );
    y = find_daddy_cyc( b );
    daddy_cyc[x] = y;
}

int construct( vector<vector<int>> p) {
    int n = p.size();
    for (int i = 0; i < n; i++) {
        vector<int> row;
        row.resize(n);
        answer.push_back(row);
    }

    int i, j;
    bool ok = true;

    for( i = 0; i < n; i++ ) {
        for( j = 0; j < n; j++ )
            if( p[i][j] == 3 )
                ok = false;
    }
    if( !ok )
        return 0;
    for( i = 0; i < n; i++ )
        daddy[i] = daddy_cyc[i] = i;
    for( i = 0; i < n; i++ ) {
        for( j = 0; j < n; j++ )
            if( p[i][j] == 1 )
                marry_daddy( i, j );
    }
    for( i = 0; i < n; i++ ) {
        for( j = 0; j < n; j++ )
            if( p[i][j] != 1 && find_daddy(i) == find_daddy(j) )
                ok = false;
    }
    if( !ok )
        return 0;
    for( i = 0; i < n; i++ )
        if( find_daddy(i) != i ) {
            answer[i][find_daddy(i)] = 1;
            answer[find_daddy(i)][i] = 1;
        }

    for( i = 0; i < n; i++ ) {
        for( j = 0; j < n; j++ )
            if( p[i][j] == 2 )
                marry_daddy_cyc(find_daddy(i), find_daddy(j) );
    }
    for( i = 0; i < n; i++ ) {
        for( j = 0; j < n; j++ )
            if( p[i][j] < 2 && find_daddy(i) != find_daddy(j) && find_daddy_cyc(find_daddy(i)) == find_daddy_cyc(find_daddy(j)) )
                ok = false;
    }
    if( !ok )
        return 0;

    for( i = 0; i < n; i++ ) {
        if( find_daddy_cyc(i) != i )
            cyc[find_daddy_cyc(i)].push_back(i);
    }

    for( i = 0; i < n; i++ ) {
        if( cyc[i].size() == 1 )
            ok = false;
        if( cyc[i].size() >= 2 ) {
            for( j = 0; j < cyc[i].size() - 1; j++ ) {
                answer[cyc[i][j+1]][cyc[i][j]] = 1;
                answer[cyc[i][j]][cyc[i][j+1]] = 1;
            }
            answer[i][cyc[i][0]] = 1;
            answer[cyc[i][0]][i] = 1;
            answer[i][cyc[i][j]] = 1;
            answer[cyc[i][j]][i] = 1;
        }
    }
    if( !ok )
        return 0;
    build(answer);
    return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:102:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  102 |             for( j = 0; j < cyc[i].size() - 1; 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