Submission #789619

#	Time	Username	Problem	Language	Result	Execution time	Memory
789619		esomer	Toy Train (IOI17_train)	C++17	49 / 100	2047 ms	1356 KiB

train

#include<bits/stdc++.h>
#include "train.h"

using namespace std;

typedef long long ll;

//~ vector<int> who_wins2(vector<int> A, vector<int> R, vector<int> U, vector<int> V){
	//~ int n = (int)A.size();
	//~ int m = (int)U.size();
	//~ bool first = 1;
	//~ for(int i = 0; i < m; i++){
		//~ if(V[i] != U[i] && V[i] != U[i] + 1) first = 0;
	//~ }
	//~ if(first){
		//~ vector<bool> self(n, 0);
		//~ vector<bool> other(n, 0);
		//~ for(int i = 0; i < m; i++){
			//~ if(U[i] == V[i]) self[U[i]] = 1;
			//~ else other[U[i]] = 1;
		//~ }
		//~ vector<int> ans(n, 0);
		//~ for(int i = n - 1; i >= 0; i--){
			//~ if(A[i] == 1){
				//~ if(self[i] == 1 && R[i] == 1) ans[i] = 1;
				//~ else if(other[i] == 1) ans[i] = ans[i+1];
			//~ }else{
				//~ if(self[i] == 1){
					//~ if(R[i] == 0) ans[i] = 0;
					//~ else{
						//~ if(other[i]) ans[i] = ans[i+1];
						//~ else ans[i] = 1;
					//~ }
				//~ }else if(other[i] == 1) ans[i] = ans[i+1];
			//~ }
		//~ }
		//~ return ans;
	//~ }else return {};
//~ }

void process(vector<int>& A, vector<int>& R, vector<int>& U, vector<int>& V, vector<bool>& forced){
	int n = (int)A.size();
	int m = (int)U.size();
	vector<vector<int>> radj(n);
	vector<int> out(n, 0);
	for(int i = 0; i < m; i++){
		if(R[U[i]] == 1) continue;
		out[U[i]]++;
		radj[V[i]].push_back(U[i]);
	}
	queue<int> q;
	for(int i = 0; i < n; i++){
		if(out[i] == 0){
			forced[i] = 0;
			q.push(i);
		}
	}
	while(!q.empty()){
		int x = q.front(); q.pop();
		for(int node : radj[x]){
			out[node]--;
			if(out[node] == 0 && forced[node] == 1) {q.push(node); forced[node] = 0;}
			if(A[node] == 1 && forced[node] == 1){
				forced[node] = 0;
				q.push(node);
			}
		}
	}
	radj.assign(n, {});
	out.assign(n, 0);
	for(int i = 0; i < m; i++){
		if(forced[U[i]] == 1) continue;
		out[U[i]]++;
		radj[V[i]].push_back(U[i]);
	}
	for(int i = 0; i < n; i++){
		if(out[i] == 0){
			q.push(i);
		}
	}
	while(!q.empty()){
		int x = q.front(); q.pop();
		for(int node : radj[x]){
			out[node]--;
			if(out[node] == 0 && forced[node] == 0) {q.push(node); forced[node] = 1;}
			if(A[node] == 0 && forced[node] == 0){
				forced[node] = 1;
				q.push(node);
			}
		}
	}
}

vector<int> who_wins(vector<int> A, vector<int> R, vector<int> U, vector<int> V){
	int n = (int)A.size();
	int m = (int)U.size();
	bool stop = 0;
	vector<bool> forced; //If 1, then it can be forced by B into a cycle with no R's.
	while(!stop){
		stop = 1;
		forced.assign(n, 1);
		process(A, R, U, V, forced);
		for(int i = 0; i < n; i++){
			if(forced[i] == 1 && R[i] == 1) {R[i] = 0; stop = 0;}
		}
	}
	vector<int> ans(n);
	for(int i = 0; i < n; i++){
		if(forced[i] == 1) ans[i] = 0;
		else ans[i] = 1;
	}
	return ans;
}

//~ mt19937 gen(time(0));

//~ void generate(){
	//~ for(int tt = 0; tt <= 10000; tt++){
		//~ int n = gen() % 5 + 1;
		//~ int m = gen() % 5 + n;
		//~ vector<int> a(n), r(n), u(m), v(m);

		//~ for(int i = 0; i < n; i++)
			//~ a[i] = gen() % 2;

		//~ for(int i = 0; i < n; i++)
			//~ r[i] = gen() % 2;

		//~ for(int i = 0; i < n; i++){
			//~ u[i] = i;
			//~ if(u[i] == n - 1) v[i] = u[i];
			//~ else v[i] = u[i] + gen() % 2;
		//~ }
		//~ for(int i = n; i < m; i++){
			//~ u[i] = gen() % n;
			//~ if(u[i] == n - 1) v[i] = u[i];
			//~ else v[i] = u[i] + gen() % 2;
		//~ }
		//~ vector<int> res = who_wins(a, r, u, v);
		//~ vector<int> res2 = who_wins2(a, r, u, v);

		//~ if(res != res2){
			//~ cout << n << " " << m << endl;
			//~ for(int x : a) cout << x << " ";
			//~ cout << endl;
			//~ for(int x : r) cout << x << " "; cout << endl;
			//~ for(int i = 0; i < m; i++){
				//~ cout << u[i] << " " << v[i] << endl;
			//~ }
			//~ cout << "RES: ";
			//~ for(int x : res) cout << x << " "; cout << endl;
			//~ cout << "RES2: ";
			//~ for(int x : res2) cout << x << " "; cout << endl;
			//~ return;
		//~ }
	//~ }
//~ }

//~ int main() {
	
	//~ generate(); return 0;

	//~ freopen("in.txt", "r", stdin);

	//~ int n, m;
	//~ assert(2 == scanf("%d %d", &n, &m));
 
	//~ vector<int> a(n), r(n), u(m), v(m);
 
	//~ for(int i = 0; i < n; i++)
		//~ assert(1 == scanf("%d", &a[i]));
 
	//~ for(int i = 0; i < n; i++)
		//~ assert(1 == scanf("%d", &r[i]));
 
	//~ for(int i = 0; i < m; i++)
		//~ assert(2 == scanf("%d %d", &u[i], &v[i]));
 
	//~ vector<int> res = who_wins(a, r, u, v);
 
	//~ for(int i = 0; i < (int)res.size(); i++)
		//~ printf(i ? " %d" : "%d", res[i]);
	//~ printf("\n");

	//~ return 0;
//~ }

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:96:6: warning: unused variable 'm' [-Wunused-variable]
   96 |  int m = (int)U.size();
      |      ^

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 11 / 11
• Subtask 4: 11 / 11
• Subtask 5: 12 / 12
• Subtask 6: 0 / 51