Submission #439456

#	Time	Username	Problem	Language	Result	Execution time	Memory
439456		flappybird	Toy Train (IOI17_train)	C++14	100 / 100	695 ms	1856 KiB

train

#include "train.h"

#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2,fma")

using namespace std;
typedef int ll;

#define MAX 6000

vector<ll> A, s;
ll N, M;
vector<ll> adj[MAX], rev[MAX], deg, d;
ll mp[MAX][MAX];

std::vector<int> who_wins(std::vector<int> a, std::vector<int> r, std::vector<int> u, std::vector<int> v) {
	ll i;
	A = a;
	N = a.size();
	M = u.size();
	vector<ll> res, ans;
	ans.resize(N);
	for (i = 0; i < N; i++) if (r[i]) s.push_back(i);
	for (i = 0; i < M; i++) adj[u[i]].push_back(v[i]), rev[v[i]].push_back(u[i]);
	d.resize(N);
	deg.resize(N);
	res.resize(N);
	ll T;
	for (T = 1; T <= N; T++) {
		bool chk = true;
		for (i = 0; i < N; i++) {
			res[i] = 0;
			d[i] = 0;
			deg[i] = 0;
			if (ans[i]) continue;
			for (auto x : adj[i]) {
				if (ans[x]) continue;
				d[i]++;
				deg[i]++;
			}
		}
		queue<ll> q;
		for (auto st : s) {
			if (ans[st]) continue;
			q.push(st);
			res[st] = 1;
		}
		ll j;
		while (!q.empty()) {
			ll t = q.front();
			q.pop();
			for (auto x : rev[t]) {
				if (ans[x]) continue;
				if (res[x]) continue;
				deg[x]--;
				if (a[x]) q.push(x), res[x] = 1;
				else if (deg[x] <= 0) q.push(x), res[x] = 1;
			}
		}
		//impossible
		deg = d;
		vector<ll> imp;
		for (i = 0; i < N; i++) if (!res[i]) imp.push_back(i);
		while (!q.empty()) q.pop();
		for (auto st : imp) {
			if (ans[st]) continue;
			q.push(st);
			ans[st] = 1;
			chk = false;
		}
		while (!q.empty()) {
			ll t = q.front();
			q.pop();
			for (auto x : rev[t]) {
				if (ans[x]) continue;
				deg[x]--;
				if (!a[x]) q.push(x), ans[x] = 1, chk = false;
				else if (deg[x] <= 0) q.push(x), ans[x] = 1, chk = false;
			}
		}
		if (chk) break;
	}
	for (i = 0; i < N; i++) ans[i] = !ans[i];
	return ans;
}

Compilation message (stderr)

train.cpp: In function 'std::vector<int> who_wins(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
train.cpp:51:6: warning: unused variable 'j' [-Wunused-variable]
   51 |   ll j;
      |      ^

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 11 / 11
• Subtask 4: 11 / 11
• Subtask 5: 12 / 12
• Subtask 6: 51 / 51