Submission #631198

#	Time	Username	Problem	Language	Result	Execution time	Memory
631198		NintsiChkhaidze	One-Way Streets (CEOI17_oneway)	C++14	30 / 100	3043 ms	15540 KiB

oneway

#include <bits/stdc++.h>
#define s second
#define f first
#define pb push_back
using namespace std;

const int N = 100005;
vector <pair<int,int> > v[N];
int tin[N],low[N],a[N],b[N];
vector <int> open[N],close[N];
bool bridge[N],vis[N],F[N];
int f[N],o,c,cnt;

void dfs(int x,int par){
    f[x] = 1;
    tin[x] = low[x] = cnt++;
    for (auto [to,id]: v[x]){
        if (to == par) continue;
        if (f[to]){
            low[x] = min(low[x], tin[to]);
        }else{
            dfs(to,x);
            low[x] = min(low[x], low[to]);
            if (low[to] > tin[x])
                bridge[id] = 1;
        }
    }
}

void DFS(int x){
    vis[x] = 1;
    for (int y: open[x]){
        o++;
        f[y]++;
        if (f[y] == 0) o--,c--;
    }

    for (int y: close[x]){
        c++;
        f[y]--;
        if (f[y] == 0) c--,o--;
    }

    for (auto [to,id]: v[x])
        if (!vis[to] && !F[id]) DFS(to);
    
}

int main (){
    ios_base::sync_with_stdio(0),cin.tie(NULL),cout.tie(NULL);
    int n,m;
    cin>>n>>m;

    for (int i = 1; i <= m; i++){
        cin>>a[i]>>b[i];
        v[a[i]].pb({b[i],i});
        v[b[i]].pb({a[i],i});
    }
    
    for (int i= 1; i <= n; i++)
        if (!f[i]) dfs(i,i); 

    int k;
    cin>>k;
    for (int i = 1; i <= k; i++){
        int x,y;
        cin>>x>>y;
        open[x].pb(i);
        close[y].pb(i);
    }

    for (int i = 1; i <= m; i++){
        if (bridge[i] == 0) cout<<'B';
        else{
            o = 0,c=0;
            for (int j=1;j<=k;j++) f[j] = 0;
            for (int j=1;j<=n;j++) vis[j] = 0;
            F[i] = 1;
            DFS(a[i]);
            F[i] = 0;
            if(o && !c) cout<<'R';
            else if (!o && c) cout<<'L';
            else cout<<'B';
        }
    }

}

Compilation message (stderr)

oneway.cpp: In function 'void dfs(int, int)':
oneway.cpp:17:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   17 |     for (auto [to,id]: v[x]){
      |               ^
oneway.cpp: In function 'void DFS(int)':
oneway.cpp:44:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   44 |     for (auto [to,id]: v[x])
      |               ^

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