Submission #45492

#	Time	Username	Problem	Language	Result	Execution time	Memory
45492		Abelyan	Toy Train (IOI17_train)	C++17	49 / 100	2071 ms	1852 KiB

train

#include "train.h"
#include <algorithm>
#include <vector>
#include <unordered_set>
#include <queue>

#pragma GCC optimize("unroll-loops")
using namespace std;

const int N = 5006;
int n, m;
vector<int> g[N],ing[N];
bool col[N],chrg[N];


void rev(vector<bool> &s, vector<bool> &ans){
	for (int i = 0; i < n; i++){
		if (s[i] == 0) ans[i]=1;
	}
}
void fa(vector<bool> &s, vector<bool> &ans){
	
	queue<int> q;
	for (int i = 0; i < s.size(); i++){
		if (s[i]){
			q.push(i);
			ans[i] = 1;
		}
	}
	while (!q.empty()){
		int v = q.front();
		q.pop();
		for (auto to : ing[v]){
			if (ans[to]) continue;
			bool mb = true;
			for (auto k : g[to]){
				mb &= ans[k] == 1;
			}
			if (col[to] || mb){
				ans[to]=1;
				q.push(to);
			}
		}
	}
}

void fb(vector<bool> &s, vector<bool> &ans){
	queue<int> q;
	for (int i = 0; i < s.size();i++){
		if (s[i]){
			q.push(i);
			ans[i] = 1;
		}
	}
	while (!q.empty()){
		int v = q.front();
		q.pop();
		for (auto to : ing[v]){
			if (ans[to]) continue;
			bool mb = true;
			for (auto k : g[to]){
				mb &= ans[k] == 1;
			}
			if (!col[to] || mb){
				ans[to] = 1;
				q.push(to);
			}
		}
	}
}

void intersect(vector<bool> &a, vector<bool> &b, vector<bool> &ans){
	for (int i = 0; i < a.size();i++){
		if (b[i] && a[i]) ans[i]=1;
	}
}

vector<int> who_wins(vector<int> a, vector<int> r, vector<int> u, vector<int> v) {
	n = a.size();
	m = u.size();
	for (int i = 0; i < m; i++){
		g[u[i]].push_back(v[i]);
		ing[v[i]].push_back(u[i]);
	}
	for (int i = 0; i < n; i++){
		if (a[i]){
			col[i] = true;
		}
	}
	for (int i = 0; i < n; i++){
		if (r[i]) chrg[i] = true;
	}
	
	while (1){
		vector<bool> R(n);
		for (int i = 0; i < n; i++){
			if (chrg[i]) R[i]=1;
		}
		vector<bool>  far(n), gg(n) , x(n), ht(n);
		fa(R, far);
		rev(far, gg);
		fb(gg, x);
		intersect(far, x, ht);
		bool mb = false;
		for (int i = 0; i < ht.size();i++){
			if (ht[i] && chrg[i]) mb = true, chrg[i] = false;
		}
		if (!mb){
			vector<int> ans(n,1);
			for (int i = 0; i < x.size();i++){
				if (x[i])
					ans[i] = 0;
			}
			return ans;
		}
	}
}
/*
2 4 
0 1 
1 0 
0 0 
0 1 
1 0 
1 1 

*/

Compilation message (stderr)

train.cpp: In function 'void fa(std::vector<bool>&, std::vector<bool>&)':
train.cpp:24:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < s.size(); i++){
                  ~~^~~~~~~~~~
train.cpp: In function 'void fb(std::vector<bool>&, std::vector<bool>&)':
train.cpp:49:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < s.size();i++){
                  ~~^~~~~~~~~~
train.cpp: In function 'void intersect(std::vector<bool>&, std::vector<bool>&, std::vector<bool>&)':
train.cpp:73:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < a.size();i++){
                  ~~^~~~~~~~~~
train.cpp: In function 'std::vector<int> who_wins(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
train.cpp:105:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < ht.size();i++){
                   ~~^~~~~~~~~~~
train.cpp:110:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int i = 0; i < x.size();i++){
                    ~~^~~~~~~~~~

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