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Submission #425903

# Submission time Handle Problem Language Result Execution time Memory
425903 2021-06-13T12:17:21 Z oleh1421 One-Way Streets (CEOI17_oneway) C++17
60 / 100
 3000 ms 18008 KB 
#include<bits/stdc++.h>
typedef long long ll;
using namespace std;
const int N=100010;
const ll mod=1000000007;
const ll inf=1e15;
int a[N],b[N];
int x[N],y[N];
vector<pair<int,int> >g[N];
int timer=0;
int tin[N],tout[N],fup[N];
bool used[N];
bool imp[N];
void dfs(int v,int pr){
    used[v]=true;
    tin[v]=fup[v]=++timer;
    for (auto cur:g[v]){
        int to=cur.first;
        int ind=cur.second;
        if (ind==pr) continue;
        if (!used[to]){
            dfs(to,ind);
            if (fup[to]>tin[v]) imp[ind]=true;
            fup[v]=min(fup[v],fup[to]);
        } else {
            fup[v]=min(fup[v],tin[to]);
        }
    }
}
int comp[N];
int num=0;
void dfs1(int v){
    comp[v]=num;
    for (auto cur:g[v]){
        int to=cur.first;
        int ind=cur.second;
        if (!imp[ind] && !comp[to]){
            dfs1(to);
        }
    }
}
vector<pair<int,int> >t[N];
const int L=20;
int up[N][L];

void dfs2(int v,int pr){
    up[v][0]=pr;
//    cout<<"0 "<<v<<" "<<pr<<endl;
    for (int i=1;i<L;i++){
        up[v][i]=up[up[v][i-1]][i-1];

    }
    used[v]=true;
    tin[v]=++timer;
    for (auto cur:t[v]){
        int to=cur.first;
        int ind=cur.second;
        if (to==pr) continue;
        dfs2(to,v);
    }

    tout[v]=timer;
}
bool upper(int a,int b){
    return (tin[a]<=tin[b] && tout[b]<=tout[a]);
}
int lca(int a,int b){
    if (upper(a,b)) return a;
    if (upper(b,a)) return b;
    for (int i=L-1;i>=0;i--){
        if (!upper(up[a][i],b)) a=up[a][i];
    }
    return up[a][0];
}
int add[N][2];
char ans[N];
void dfs3(int v,int pr,int ind){
    used[v]=true;
    for (auto cur:t[v]){
        int to=cur.first;
        int ind=cur.second;
        if (to==pr) continue;
        dfs3(to,v,ind);
        add[v][0]+=add[to][0];
        add[v][1]+=add[v][1];
    }
//    if (add[v][0] && add[v][1]) exit(1);
    if (add[v][0]){
        if (comp[a[ind]]==v) ans[ind]='R';
        else ans[ind]='L';
    } else if (add[v][1]){
        if (comp[a[ind]]==v) ans[ind]='L';
        else ans[ind]='R';
    } else {

    }

}
pair<int,int> p[N];
void dfs4(int v){
    used[v]=true;
    for (auto cur:t[v]){
        int to=cur.first;
        int ind=cur.second;
        if (used[to]) continue;
        p[to]={v,ind};
        dfs4(to);
    }

}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n,m;cin>>n>>m;
    for (int i=1;i<=m;i++){
        cin>>a[i]>>b[i];
        g[a[i]].push_back({b[i],i});
        g[b[i]].push_back({a[i],i});
        ans[i]='B';
    }
    int k;cin>>k;
    for (int i=1;i<=k;i++){
        cin>>x[i]>>y[i];
    }
    for (int i=1;i<=n;i++){
        if (!used[i]){
            dfs(i,0);
        }
    }

    for (int i=1;i<=n;i++){
        if (!comp[i]){
            num++;
            dfs1(i);
        }
    }
    for (int v=1;v<=n;v++){
        for (auto cur:g[v]){
            int to=cur.first;
            int ind=cur.second;
            if (imp[ind]){
                t[comp[v]].push_back({comp[to],ind});
            }
        }
    }
    for (int i=1;i<=k;i++){
        for (int j=1;j<=n;j++) used[j]=false;
        x[i]=comp[x[i]];
        y[i]=comp[y[i]];
        dfs4(x[i]);
        int cur=y[i];
        while (cur!=x[i]){
            int to=p[cur].first;
            int ind=p[cur].second;
            if (comp[a[ind]]==to) ans[ind]='R';
            else ans[ind]='L';
            cur=to;
        }
    }
//    for (int i=1;i<=n;i++) used[i]=false,tin[i]=0;
//    tin[0]=0;
//    timer=0;
//    for (int i=1;i<=num;i++){
//        if (!used[i]) dfs2(i,0);
//    }
//    tout[0]=timer;
//    for (int i=1;i<=k;i++){
//        x[i]=comp[x[i]];
//        y[i]=comp[y[i]];
//        int lc=lca(x[i],y[i]);
//        add[x[i]][0]++;
//        add[y[i]][1]++;
//        add[lc][0]--;
//        add[lc][1]--;
//    }
//    for (int i=1;i<=num;i++) used[i]=false;
//    for (int i=1;i<=num;i++) {
//        if (!used[i]){
//            dfs3(i,0,0);
//        }
//    }
    for (int i=1;i<=m;i++) cout<<ans[i];
    cout<<endl;
    return 0;
}

Compilation message

oneway.cpp: In function 'void dfs2(int, int)':
oneway.cpp:57:13: warning: unused variable 'ind' [-Wunused-variable]
   57 |         int ind=cur.second;
      |             ^~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 5068 KB Output is correct
2 Correct 5 ms 4940 KB Output is correct
3 Correct 5 ms 5068 KB Output is correct
4 Correct 5 ms 5068 KB Output is correct
5 Correct 7 ms 5196 KB Output is correct
6 Correct 4 ms 5068 KB Output is correct
7 Correct 7 ms 5200 KB Output is correct
8 Correct 6 ms 5068 KB Output is correct
9 Correct 4 ms 5068 KB Output is correct
10 Correct 5 ms 5068 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 5068 KB Output is correct
2 Correct 5 ms 4940 KB Output is correct
3 Correct 5 ms 5068 KB Output is correct
4 Correct 5 ms 5068 KB Output is correct
5 Correct 7 ms 5196 KB Output is correct
6 Correct 4 ms 5068 KB Output is correct
7 Correct 7 ms 5200 KB Output is correct
8 Correct 6 ms 5068 KB Output is correct
9 Correct 4 ms 5068 KB Output is correct
10 Correct 5 ms 5068 KB Output is correct
11 Correct 52 ms 10156 KB Output is correct
12 Correct 62 ms 11180 KB Output is correct
13 Correct 71 ms 12280 KB Output is correct
14 Correct 114 ms 13620 KB Output is correct
15 Correct 187 ms 14236 KB Output is correct
16 Correct 115 ms 15536 KB Output is correct
17 Correct 1359 ms 17020 KB Output is correct
18 Correct 1109 ms 15548 KB Output is correct
19 Correct 1442 ms 18008 KB Output is correct
20 Correct 69 ms 10712 KB Output is correct
21 Correct 56 ms 10468 KB Output is correct

Subtask #3
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 5068 KB Output is correct
2 Correct 5 ms 4940 KB Output is correct
3 Correct 5 ms 5068 KB Output is correct
4 Correct 5 ms 5068 KB Output is correct
5 Correct 7 ms 5196 KB Output is correct
6 Correct 4 ms 5068 KB Output is correct
7 Correct 7 ms 5200 KB Output is correct
8 Correct 6 ms 5068 KB Output is correct
9 Correct 4 ms 5068 KB Output is correct
10 Correct 5 ms 5068 KB Output is correct
11 Correct 52 ms 10156 KB Output is correct
12 Correct 62 ms 11180 KB Output is correct
13 Correct 71 ms 12280 KB Output is correct
14 Correct 114 ms 13620 KB Output is correct
15 Correct 187 ms 14236 KB Output is correct
16 Correct 115 ms 15536 KB Output is correct
17 Correct 1359 ms 17020 KB Output is correct
18 Correct 1109 ms 15548 KB Output is correct
19 Correct 1442 ms 18008 KB Output is correct
20 Correct 69 ms 10712 KB Output is correct
21 Correct 56 ms 10468 KB Output is correct
22 Execution timed out 3089 ms 17768 KB Time limit exceeded
23 Halted 0 ms 0 KB -