Submission #701974

#	Time	Username	Problem	Language	Result	Execution time	Memory
701974		PenguinsAreCute	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	197 ms	24064 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>
using namespace std;
int par[1005];
int find_set(int x) {
    if(par[x] == x) return x;
    return par[x] = find_set(par[x]);
}
bool same_set(int x, int y) {
    return find_set(x) == find_set(y);
}
void merge_set(int x, int y) {
    par[find_set(x)] = find_set(y);
}
int construct(vector<vector<int>> p) {
    for(int i = 0; i < 1005; i++) par[i] = i;
	int n = p.size();
	vector<vector<int>> answer;
	for(int i = 0; i < n; i++) {
		vector<int> row;
		for(int j = 0; j < n; j++) row.push_back(0);
		answer.push_back(row);
	}
	for (int i = 0; i < n; i++) {
		for(int j = 0; j < n; j++) {
			if(p[i][j] == 3) return 0;
            if(p[i][j] != 0 && !same_set(i, j)) merge_set(i, j);
        }
	}
    for(int i = 0; i < n; i++) for(int j = 0; j < n; j++) if(i != j && same_set(i, j) != (bool)p[i][j]) return 0;
    for(int i = 0; i < n; i++) {
		vector<int> v, c;
		for(int j = 0; j < n; j++) if(find_set(j) == i) v.push_back(j);
		if(v.size() == 2 && p[v[0]][v[1]] == 2) return 0;
		if(v.size() != 0) {
			int s = v.size();
			for(int j = 0; j < s; j++) {
				bool inC = true;
				for(int k = 0; k < j; k++) if(p[v[j]][v[k]] == 1) {
					answer[v[j]][v[k]] = 1;
					answer[v[k]][v[j]] = 1;
					inC = false; break;
				}
				if(inC) c.push_back(v[j]);
			}
			for(int i = 0; i < c.size() - 1; i++) {
				answer[c[i]][c[i + 1]] = 1;
				answer[c[i + 1]][c[i]] = 1;
			}
			if(c.size() > 1) {
				answer[c[0]][c[c.size() - 1]] = 1;
				answer[c[c.size() - 1]][c[0]] = 1;
			}
		}
    }
	build(answer);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:46:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |    for(int i = 0; i < c.size() - 1; i++) {
      |                   ~~^~~~~~~~~~~~~~

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