oj.uz

답안 #425927

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
425927 2021-06-13T12:26:18 Z oleh1421 One-Way Streets (CEOI17_oneway) C++17
60 / 100
 3000 ms 18004 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 nxt=cur.second;
        if (to==pr) continue;
        dfs3(to,v,nxt);
        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++){
        x[i]=comp[x[i]];
        y[i]=comp[y[i]];
    }
    for (int i=1;i<=k;i++){
        for (int j=1;j<=n;j++) used[j]=false;
        int lc=lca(x[i],y[i]);
        dfs4(lc);
        int cur=y[i];
        while (cur!=lc){
            int to=p[cur].first;
            int ind=p[cur].second;
            if (comp[a[ind]]==to) {
                ans[ind]='R';

            }
            else {

                ans[ind]='L';
            }
            cur=to;
        }
        cur=x[i];
        while (cur!=lc){
            int to=p[cur].first;
            int ind=p[cur].second;
            if (comp[a[ind]]==to) {
                ans[ind]='L';
            }
            else {

                ans[ind]='R';
            }
            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++){
//        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

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 4940 KB Output is correct
2 Correct 4 ms 5016 KB Output is correct
3 Correct 4 ms 5068 KB Output is correct
4 Correct 4 ms 5084 KB Output is correct
5 Correct 6 ms 5196 KB Output is correct
6 Correct 4 ms 5068 KB Output is correct
7 Correct 6 ms 5140 KB Output is correct
8 Correct 6 ms 5068 KB Output is correct
9 Correct 4 ms 5068 KB Output is correct
10 Correct 4 ms 5196 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 4940 KB Output is correct
2 Correct 4 ms 5016 KB Output is correct
3 Correct 4 ms 5068 KB Output is correct
4 Correct 4 ms 5084 KB Output is correct
5 Correct 6 ms 5196 KB Output is correct
6 Correct 4 ms 5068 KB Output is correct
7 Correct 6 ms 5140 KB Output is correct
8 Correct 6 ms 5068 KB Output is correct
9 Correct 4 ms 5068 KB Output is correct
10 Correct 4 ms 5196 KB Output is correct
11 Correct 47 ms 10184 KB Output is correct
12 Correct 55 ms 11096 KB Output is correct
13 Correct 73 ms 12256 KB Output is correct
14 Correct 119 ms 13636 KB Output is correct
15 Correct 174 ms 14200 KB Output is correct
16 Correct 137 ms 15556 KB Output is correct
17 Correct 1313 ms 17028 KB Output is correct
18 Correct 848 ms 15536 KB Output is correct
19 Correct 1146 ms 18004 KB Output is correct
20 Correct 70 ms 10712 KB Output is correct
21 Correct 60 ms 10556 KB Output is correct

Subtask #3
0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 4940 KB Output is correct
2 Correct 4 ms 5016 KB Output is correct
3 Correct 4 ms 5068 KB Output is correct
4 Correct 4 ms 5084 KB Output is correct
5 Correct 6 ms 5196 KB Output is correct
6 Correct 4 ms 5068 KB Output is correct
7 Correct 6 ms 5140 KB Output is correct
8 Correct 6 ms 5068 KB Output is correct
9 Correct 4 ms 5068 KB Output is correct
10 Correct 4 ms 5196 KB Output is correct
11 Correct 47 ms 10184 KB Output is correct
12 Correct 55 ms 11096 KB Output is correct
13 Correct 73 ms 12256 KB Output is correct
14 Correct 119 ms 13636 KB Output is correct
15 Correct 174 ms 14200 KB Output is correct
16 Correct 137 ms 15556 KB Output is correct
17 Correct 1313 ms 17028 KB Output is correct
18 Correct 848 ms 15536 KB Output is correct
19 Correct 1146 ms 18004 KB Output is correct
20 Correct 70 ms 10712 KB Output is correct
21 Correct 60 ms 10556 KB Output is correct
22 Execution timed out 3080 ms 17852 KB Time limit exceeded
23 Halted 0 ms 0 KB -