Submission #968774

#	Time	Username	Problem	Language	Result	Execution time	Memory
968774		beaboss	Connecting Supertrees (IOI20_supertrees)	C++14	11 / 100	175 ms	27948 KiB

supertrees

// Source:https://ioinformatics.org/files/ioi2020problem2.pdf
// 
#include "supertrees.h"
#include "bits/stdc++.h"

using namespace std;

#define s second
#define f first
#define pb push_back

typedef long long ll;

typedef pair<int, int> pii;
typedef vector<pii> vpii;

typedef vector<int> vi;

#define FOR(i, a, b) for (int i = (a); i<b; i++)

bool ckmin(int& a, int b){ return b < a ? a = b, true : false; }

bool ckmax(int& a, int b){ return b > a ? a = b, true : false; }

vector<vi> pth;
vector<vi> sol;
int n;
vector<bool> vis;
bool works=true;
vector<vi> p;

void solve(vi here) {
	// cout << 'd' << endl;
	vi cyc;
	vi ncyc;
	for (auto i: here) {
		bool fail=true;
		for (auto j: here) {
			if (i != j && p[i][j] != 2) {
				fail=false;
			}
		}

		if (!fail) ncyc.pb(i);
		else cyc.pb(i);
	}


	for (auto i: ncyc) {
		for (auto j: ncyc)  {
			if (p[i][j] != 1) works=false;
			// cout << i << j << p[i][j] << endl;
		}
	}


	int chosen;
	if (ncyc.size()) {
		chosen = ncyc.back();
		ncyc.pop_back();
	}
	// cout << cyc.size() << endl;
	FOR(i, 0, ((int) cyc.size()) - 1) {
		// cout << cyc[i] << endl;
		sol[cyc[i]][cyc[i + 1]] = 1;
		sol[cyc[i + 1]][cyc[i]] = 1;
	}
	// cout << 'd' << endl;

	if (cyc.size() && ncyc.size()) {
		sol[chosen][cyc[0]]=1;
		sol[cyc[0]][chosen]=1;

		sol[chosen][cyc[cyc.size() - 1]]=1;
		sol[cyc[cyc.size() - 1]][chosen]=1;
	}

	if (ncyc.size()) {
		sol[ncyc[0]][chosen] = 1;
		sol[chosen][ncyc[0]] = 1;
		FOR(i, 0, ncyc.size() - 1) {
			sol[ncyc[i]][ncyc[i + 1]] = 1;
			sol[ncyc[i + 1]][ncyc[i]] = 1;
		}
	}


}

// void build(vector<vi> t) {
// 	for (auto val: t) {
// 		for (auto j: val) {
// 			cout << j << ' ';
// 		}
// 		cout << endl;
// 	}
// }
int construct(vector<vi> P) {
	n = P.size();
	p = P;
	sol = vector<vi>(n, vi(n, 0));
	vis.resize(n);
	FOR(i, 0, n) {
		if (!vis[i]) {
			vi here;
			FOR(j, 0, n) {
				if (p[i][j]) {
					vis[j]=true;
					here.pb(j);
				}
			}
			// cout << i << endl;
			solve(here);
		}
	}
	if (!works) return 0;

	build(sol);
	return 1;

}



// int main() {
// 	ios::sync_with_stdio(false);
// 	cin.tie(nullptr);

// 	// cout << construct({{1, 1, 2, 2}, {1, 1, 2, 2}, {2, 2, 1, 2}, {2, 2, 2, 1}}) << endl;
// 	cout << construct({{1, 1}, {1, 1}}) << endl;

// }

Compilation message (stderr)

supertrees.cpp: In function 'void solve(vi)':
supertrees.cpp:19:41: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 | #define FOR(i, a, b) for (int i = (a); i<b; i++)
......
   81 |   FOR(i, 0, ncyc.size() - 1) {
      |       ~~~~~~~~~~~~~~~~~~~~~              
supertrees.cpp:81:3: note: in expansion of macro 'FOR'
   81 |   FOR(i, 0, ncyc.size() - 1) {
      |   ^~~
supertrees.cpp:71:13: warning: 'chosen' may be used uninitialized in this function [-Wmaybe-uninitialized]
   71 |   sol[chosen][cyc[0]]=1;
      |             ^

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