Submission #304480

#	Time	Username	Problem	Language	Result	Execution time	Memory
304480		Leonardo_Paes	Connecting Supertrees (IOI20_supertrees)	C++17	11 / 100	273 ms	22096 KiB

supertrees

#include "supertrees.h"
#include <vector>
using namespace std;
const int maxn = 1e3+10;
int pai[maxn], sz[maxn];
int find(int x){ return pai[x] = (pai[x] == x ? x : find(pai[x])); }
void join(int a, int b){
    a = find(a), b = find(b);
    if(a == b) return;
    if(sz[a] > sz[b]) swap(a, b);
    sz[b] += sz[a];
    pai[a] = b;
}
int construct(vector<vector<int> > p) {
	int n = p.size();
	vector<vector<int> > ans;
	for(int i=0; i<n; i++){
        vector<int> row;
        for(int j=0; j<n; j++){
            row.push_back(0);
        }
        ans.push_back(row);
	}
    for(int i=0; i<n; i++){
        pai[i] = i;
        sz[i] = 1;
    }
    for(int i=0; i<n; i++){
        for(int j=i+1; j<n; j++){
            if(p[i][j]) join(i, j);
        }
    }
    bool ok = 1;
    for(int i=0; i<n; i++){
        for(int j=i+1; j<n; j++){
            if(p[i][j] == 0){
                if(find(i) == find(j)) ok = 0;
            }
        }
    }
    if(!ok) return 0;
    vector<int> cc[n];
    for(int i=0; i<n; i++) cc[find(i)].push_back(i);
    for(int i=0; i<n; i++){
        if(cc[i].empty() or !ok) continue;
        for(int j=0; j<n; j++){
            pai[j] = j;
            sz[j] = 1;
        }
        for(auto x : cc[i]){
            for(auto y : cc[i]){
                if(p[x][y] == 1){
                    if(find(x) != find(y)){
                        ans[x][y] = ans[y][x] = 1;
                        join(x, y);
                    }
                }
            }
        }
        for(auto x : cc[i]){
            for(auto y : cc[i]){
                if(p[x][y] == 2){
                    if(find(x) == find(y)) ok = 0;
                }
            }
        }
        if(!ok) continue;
        vector<int> v;
        for(int j=0; j<n; j++){
            if(find(j) == j){
                v.push_back(j);
            }
        }
        if(v.size() == 1) continue;
        for(int j=0; j+1<v.size(); j++){
            ans[v[j]][v[j+1]] = ans[v[j+1]][v[j]] = 1;
        }
        ans[v.back()][v[0]] = ans[v[0]][v.back()] = 1;
    }
    if(!ok) return 0;
    build(ans);
	return 1;
	/*
6
1 2 2 1 2 2
2 1 2 2 1 2
2 2 1 2 2 1
1 2 2 1 2 2
2 1 2 2 1 2
2 2 1 2 2 1
*/
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:75:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   75 |         for(int j=0; j+1<v.size(); j++){
      |                      ~~~^~~~~~~~~

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