Submission #476286

#	Time	Username	Problem	Language	Result	Execution time	Memory
476286		cgiosy	One-Way Streets (CEOI17_oneway)	C++17	0 / 100	0 ms	204 KiB

oneway

#include <bits/stdc++.h>
using namespace std;

int main() {
	ios::sync_with_stdio(0);cin.tie(0);
	int N, M;
	cin>>N>>M;
	int E[M*2+2], F[M*2+2], G[N]{};
	for(int i=1; i<=M; i++) {
		int a, b;
		cin>>a>>b; --a, --b;
		E[i*2]=b, F[i*2]=G[a], G[a]=i*2;
		E[i*2+1]=a, F[i*2+1]=G[b], G[b]=i*2+1;
	}
	int A[N]{}, T[N], t=0, v=N, st;
	bool U[M+1]{}, V[M+1]{};
	cin>>st>>st;
	function<void(int, int)> bcc=[&](int i, int p) {
		A[i]=T[i]=++t;
		for(int e=G[i]; e; e=F[e]) if(e!=p) {
			int&j=E[e];
			if(A[j]) { T[i]=min(T[i], A[j]); continue; }
			bcc(j, e^1);
			T[i]=min(T[i], T[j]);
			U[p>>1]^=U[e>>1]^=j==st;
			U[e>>1]^=e&1;
			if(A[i]<T[j]) V[e>>1]=true;
		}
	};
	bcc(0, 0);
	for(int i=1; i<=M; i++)
		cout<<(V[i] ? U[i] ? 'R' : 'L' : 'B');
}

Compilation message (stderr)

oneway.cpp: In function 'int main()':
oneway.cpp:15:25: warning: unused variable 'v' [-Wunused-variable]
   15 |  int A[N]{}, T[N], t=0, v=N, st;
      |                         ^

• Subtask 1: 0 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40