Submission #394151

#	Time	Username	Problem	Language	Result	Execution time	Memory
394151		Pichon5	One-Way Streets (CEOI17_oneway)	C++17	0 / 100	3 ms	4940 KiB

oneway

#include<bits/stdc++.h>
#define lcm(a,b) (a/__gcd(a,b))*b
#define fast ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define ll long long int
#define vi vector<int>
#define vll vector<ll>
#define pb push_back
#define F first
#define S second
#define mp make_pair
//salida rapida "\n"
//DECIMALES fixed<<sp(n)<<x<<endl;
//gcd(a,b)= ax + by
//gcd(a,b)=gcd(a-b,b) a>=b
//lCB x&-x
//set.erase(it) - ersases the element present at the required index//auto it = s.find(element)
//set.find(element) - iterator pointing to the given element if it is present else return pointer pointing to set.end()
//set.lower_bound(element) - iterator pointing to element greater than or equal to the given element
//set.upper_bound(element) - iterator pointing to element greater than the given element
// | ^
//__builtin_popcount(x)

using namespace std;
const int MA=1e5+5;
vector<pair<int,int> > G[MA];
int vis[MA];
int arc[MA];
int num=0;
set<pair<int,int> >st;
int puente[MA];
string res;
void tarjan(int nodo, int ant){
    num++;
    vis[nodo]=arc[nodo]=num;
    for(int it =0;it<G[nodo].size();it++){
        int to=G[nodo][it].F,ind=G[nodo][it].S;
        if(ind==ant)continue;
        if(vis[to]==0){
            tarjan(to,ind);
            if(arc[to]>vis[nodo]){
                puente[ind]=1;
            }
            arc[nodo]=min(arc[nodo],arc[to]);
        }else{
            arc[nodo]=min(arc[nodo],vis[to]);
        }
    }
}
vector<pair<int,int> > G2[MA];
int C[MA];
int color=0;
void coloring(int nodo){
    cout<<nodo<<endl;
    C[nodo]=color;
    for(int i=0;i<G[nodo].size();i++){
        int to=G[nodo][i].F,ind=G[nodo][i].S;
        if(puente[ind] or C[to])continue;
        coloring(to);
    }
}
int B[MA];
void dfs(int nodo, int padre){
    for(int i=0;i<G2[nodo].size();i++){
        int to=G2[nodo][i].F,ind=G2[nodo][i].S;
        if(to==padre)continue;
        B[to]=ind;
        dfs(to,nodo);
    }
}
int main()
{
    int n,m,p,a,b;
    cin>>n>>m;
    vector<pair<int,int> >E;
    for(int i=0;i<m;i++){
        cin>>a>>b;
        G[a].pb({b,i});G[b].pb({a,i});
        E.pb({a,b});
    }
    res.assign(m,'B');
    for(int i=1;i<=n;i++){
        if(vis[i]==0){
            tarjan(i,-1);
        }
    }
    for(int i=1;i<=n;i++){
        if(C[i])continue;
        color++;
        coloring(i);
    }

    for(int i=0;i<m;i++){
        if(puente[i]==0)continue;
        int A=C[E[i].F],B=C[E[i].S];
        if(A==B)continue;
        //cout<<"UNO  "<<A<<"   "<<B<<endl;
        G2[A].pb({B,i});
        G2[B].pb({A,i});
    }
    cin>>p;
    for(int i=0;i<p;i++){
        cin>>a>>b;
        a=C[a],b=C[b];
        if(a==b)continue;
        dfs(a,-1);
        int nodo=b;
        while(nodo!=a){
            int ind=B[nodo];
            int from=C[E[ind].F];
            if(from==nodo){
                from=C[E[ind].S];
                res[ind]='L';
            }else{
                res[ind]='R';
            }
            nodo=from;
        }
    }
    cout<<res<<endl;

    return 0;
}

Compilation message (stderr)

oneway.cpp: In function 'void tarjan(int, int)':
oneway.cpp:35:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |     for(int it =0;it<G[nodo].size();it++){
      |                   ~~^~~~~~~~~~~~~~~
oneway.cpp: In function 'void coloring(int)':
oneway.cpp:55:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |     for(int i=0;i<G[nodo].size();i++){
      |                 ~^~~~~~~~~~~~~~~
oneway.cpp: In function 'void dfs(int, int)':
oneway.cpp:63:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |     for(int i=0;i<G2[nodo].size();i++){
      |                 ~^~~~~~~~~~~~~~~~

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