Submission #604361

#	Time	Username	Problem	Language	Result	Execution time	Memory
604361		thezomb1e	Connecting Supertrees (IOI20_supertrees)	C++17	11 / 100	198 ms	23312 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define eb emplace_back
#define pb push_back
#define ft first
#define sd second
#define pi pair<int, int>
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define dbg(...) dbg_out(__VA_ARGS__)

using ll = long long;
using ld = long double;
using namespace std;
using namespace __gnu_pbds;

//Constants
const ll INF = 5 * 1e18;
const int IINF = 2 * 1e9;
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
const ld PI = 3.14159265359;

//Templates
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) {return os << '(' << p.first << ", " << p.second << ')';}
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) {os << '['; string sep; for (const T &x : v) os << sep << x, sep = ", "; return os << ']';}
void dbg_out() {cerr << endl;}
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cerr << H << ' '; dbg_out(T...); }
template<typename T> void mins(T& x, T y) {x = min(x, y);}
template<typename T> void maxs(T& x, T y) {x = max(x, y);}
template<typename T> using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T> using omset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;

//order_of_key(k): number of elements strictly less than k
//find_by_order(k): k-th element in the set

void setPrec() {cout << fixed << setprecision(15);}
void unsyncIO() {cin.tie(0)->sync_with_stdio(0);}
void setIn(string s) {freopen(s.c_str(), "r", stdin);}
void setOut(string s) {freopen(s.c_str(), "w", stdout);}
void setIO(string s = "") {
    unsyncIO(); setPrec();
    if(s.size()) setIn(s + ".in"), setOut(s + ".out");
}

int construct(vector<vector<int>> p) {
	int n = p.size();
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (p[i][j] == 3) return 0;
		}
	}
	// build cycles
	vector<vector<int>> ans(n, vector<int> (n, 0));
	vector<int> comp(n, -1);
	int comp_num = 0;
	{
		vector<bool> vis(n, false);
		vector<int> path;
		function<void(int)> dfs = [&](int f) {
			vis[f] = true;
			path.pb(f);
			for (int to = 0; to < n; to++) {
				if (!vis[to] && p[f][to] == 2) {
					dfs(to);
				}
			}
		};
		for (int i = 0; i < n; i++) {
			if (!vis[i]) {
				path.clear();
				dfs(i);
				if ((int) path.size() == 2) {
					return 0;
				}
				if ((int) path.size() > 2) {
					int sz = path.size();
					for (int j = 0; j < sz; j++) {
						comp[path[j]] = comp_num;
						ans[path[j]][path[(j + 1) % sz]] = ans[path[(j + 1) % sz]][path[j]] = 1;
					}
					comp_num++;
				}
			}
		}
	}
	// build bamboos
	{
		vector<bool> vis(n, false);
		vector<int> path; set<int> comps_vis;
		function<void(int)> dfs = [&](int f) {
			vis[f] = true;
			path.pb(f);
			for (int to = 0; to < n; to++) {
				if (!vis[to]) {
					if (p[f][to] == 1)
						dfs(to);
					else if (p[f][to] == 2) 
						comps_vis.insert(comp[to]);
				}
			}
		};
		for (int i = 0; i < n; i++) {
			if (!vis[i]) {
				comps_vis.clear();
				path.clear();
				dfs(i);
				if ((int) comps_vis.size() > 1) {
					return 0;
				}
				int sz = path.size();
				for (int j = 0; j < sz - 1; j++) {
					ans[path[j]][path[j + 1]] = ans[path[j + 1]][path[j]] = 1;
				}
			}
		}
	}
	build(ans);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'void setIn(std::string)':
supertrees.cpp:43:30: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 | void setIn(string s) {freopen(s.c_str(), "r", stdin);}
      |                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
supertrees.cpp: In function 'void setOut(std::string)':
supertrees.cpp:44:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 | void setOut(string s) {freopen(s.c_str(), "w", stdout);}
      |                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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