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Submission #860321

# Submission time Handle Problem Language Result Execution time Memory
860321 2023-10-12T14:46:41 Z anton One-Way Streets (CEOI17_oneway) C++17
100 / 100
 205 ms 52052 KB 
#include<bits/stdc++.h>

using namespace std;
#define int long long
#define pii pair<int, int>

int n, m, p;
const int MAX_M = 1e5;
const int MAX_N = 1e5;

char status[MAX_M];

struct Node{
    vector<int> adj;
    vector<int> id;
    vector<int> dir;
    bool vis =false;
    int depth = 0;

    int open = 0;
} g[MAX_N], g2[MAX_N];


int dsu[MAX_N];
int sz[MAX_N];

int get(int id){
    vector<int> path;
    while(dsu[id]!=id){
        path.push_back(id);
        id = dsu[id];
    }
    for(auto e: path){
        dsu[e] = id;
    }
    return id;
}

void merge(int a, int b){

    ////cout<<a<<" and "<<b<<endl;
    a = get(a);
    b=  get(b);


    if(sz[a]<sz[b]){
        dsu[a] = b;
        sz[b] += sz[a];
    }
    else{
        dsu[b] = a;
        sz[a] += sz[b];
    }
}

int dfs(int u, int depth, int anc){
    //////cout<<"dfs "<<u<<" "<<depth<<endl;
    g[u].vis = true;
    g[u].depth = depth;
    int r = depth;
    for(int i= 0; i<g[u].adj.size(); i++){
        int v = g[u].adj[i];
        if(g[u].id[i] != anc){
            if(!g[v].vis){
                int val =dfs(v, depth+1, g[u].id[i]);
                if(val<=depth){
                    merge(u, v);
                }
                r = min(r, val);
            }
            else{
                int val = g[v].depth;
                if(val<=depth){
                    merge(u, v);
                }
                r = min(r, val);
            }
        }
    }

    return r;
}

pii edges[MAX_M];

const int MAX_P = 1e5;
pii pairs[MAX_P];

int dfs2(int id, int anc){
    g2[id].vis = true;
    int s= 0;
    for(int i = 0; i<g2[id].adj.size(); i++){
        if(g2[id].id[i] != anc){
            int c_s = dfs2(g2[id].adj[i], g2[id].id[i]);

            //cout<<g2[id].id[i]<<" "<<g2[id].dir[i]<<" "<<c_s<<endl;
            if(c_s ==0){
                status[g2[id].id[i]] = 'B';
            }
            else if(c_s >0){
                if(g2[id].dir[i] == -1){
                    status[g2[id].id[i]] = 'R';
                }  
                else{
                    status[g2[id].id[i]] = 'L';
                }
            }
            else{
                if(g2[id].dir[i] == -1){
                    status[g2[id].id[i]] = 'L';
                }
                else{
                    status[g2[id].id[i]] = 'R';
                }
            }
            s+=c_s;
        }
    }
    s+= g2[id].open;
    //cout<<id<<" "<<s<<endl;
    return s;
}

signed main(){
    cin>>n>>m;

    for(int i = 0; i<n; i++){
        dsu[i] = i;
        sz[i]=1;
    }
    for(int i = 0; i<m; i++){
        int a, b;
        cin>>a>>b;
        a--;b--;
        g[a].adj.push_back(b);
        g[b].adj.push_back(a);

        g[a].id.push_back(i);
        g[b].id.push_back(i);

        g[a].dir.push_back(1);
        g[b].dir.push_back(-1);

        edges[i].first = a;
        edges[i].second = b;
    }

    for(int i = 0; i<n; i++){

        if(!g[i].vis){
            dfs(i, 0, -1);
        }
    }

    ////cout<<"dfs done"<<endl;

    for(int i = 0; i<n; i++){
        //cout<<get(i)<<endl;
    }

    for(int i = 0; i<m; i++){
        if(get(edges[i].first) ==get(edges[i].second)){
            status[i] = 'B';
            ////cout<<i<<" ok"<<endl;
        }
        else{
            int a = get(edges[i].first);
            int b=  get(edges[i].second);
            g2[a].adj.push_back(b);
            g2[b].adj.push_back(a);
            g2[a].id.push_back(i);
            g2[b].id.push_back(i);
            g2[a].dir.push_back(1);
            g2[b].dir.push_back(-1);
        }
    }

    cin>>p;

    for(int i = 0; i<p; i++){
        cin>>pairs[i].first>>pairs[i].second;

        pairs[i].first--;pairs[i].second--;
        g2[get(pairs[i].first)].open ++;
        g2[get(pairs[i].second)].open--;
    }
    for(int i = 0; i<n; i++){
        if(!g2[get(i)].vis){
            dfs2(get(i), -1);
        }
    }

    for(int i = 0; i<m; i++){
        cout<<status[i];
    }
    cout<<endl;
}

Compilation message

oneway.cpp: In function 'long long int dfs(long long int, long long int, long long int)':
oneway.cpp:61:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |     for(int i= 0; i<g[u].adj.size(); i++){
      |                   ~^~~~~~~~~~~~~~~~
oneway.cpp: In function 'long long int dfs2(long long int, long long int)':
oneway.cpp:92:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |     for(int i = 0; i<g2[id].adj.size(); i++){
      |                    ~^~~~~~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 23644 KB Output is correct
2 Correct 5 ms 23644 KB Output is correct
3 Correct 5 ms 23644 KB Output is correct
4 Correct 5 ms 23724 KB Output is correct
5 Correct 5 ms 23900 KB Output is correct
6 Correct 5 ms 23752 KB Output is correct
7 Correct 5 ms 23900 KB Output is correct
8 Correct 6 ms 23900 KB Output is correct
9 Correct 5 ms 23644 KB Output is correct
10 Correct 6 ms 23644 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 23644 KB Output is correct
2 Correct 5 ms 23644 KB Output is correct
3 Correct 5 ms 23644 KB Output is correct
4 Correct 5 ms 23724 KB Output is correct
5 Correct 5 ms 23900 KB Output is correct
6 Correct 5 ms 23752 KB Output is correct
7 Correct 5 ms 23900 KB Output is correct
8 Correct 6 ms 23900 KB Output is correct
9 Correct 5 ms 23644 KB Output is correct
10 Correct 6 ms 23644 KB Output is correct
11 Correct 87 ms 33004 KB Output is correct
12 Correct 91 ms 34132 KB Output is correct
13 Correct 113 ms 36688 KB Output is correct
14 Correct 122 ms 39376 KB Output is correct
15 Correct 126 ms 40272 KB Output is correct
16 Correct 172 ms 47444 KB Output is correct
17 Correct 157 ms 47956 KB Output is correct
18 Correct 162 ms 47624 KB Output is correct
19 Correct 148 ms 49232 KB Output is correct
20 Correct 94 ms 34388 KB Output is correct
21 Correct 93 ms 34128 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 23644 KB Output is correct
2 Correct 5 ms 23644 KB Output is correct
3 Correct 5 ms 23644 KB Output is correct
4 Correct 5 ms 23724 KB Output is correct
5 Correct 5 ms 23900 KB Output is correct
6 Correct 5 ms 23752 KB Output is correct
7 Correct 5 ms 23900 KB Output is correct
8 Correct 6 ms 23900 KB Output is correct
9 Correct 5 ms 23644 KB Output is correct
10 Correct 6 ms 23644 KB Output is correct
11 Correct 87 ms 33004 KB Output is correct
12 Correct 91 ms 34132 KB Output is correct
13 Correct 113 ms 36688 KB Output is correct
14 Correct 122 ms 39376 KB Output is correct
15 Correct 126 ms 40272 KB Output is correct
16 Correct 172 ms 47444 KB Output is correct
17 Correct 157 ms 47956 KB Output is correct
18 Correct 162 ms 47624 KB Output is correct
19 Correct 148 ms 49232 KB Output is correct
20 Correct 94 ms 34388 KB Output is correct
21 Correct 93 ms 34128 KB Output is correct
22 Correct 205 ms 49312 KB Output is correct
23 Correct 188 ms 47952 KB Output is correct
24 Correct 189 ms 48748 KB Output is correct
25 Correct 179 ms 52052 KB Output is correct
26 Correct 199 ms 48940 KB Output is correct
27 Correct 183 ms 48124 KB Output is correct
28 Correct 73 ms 30992 KB Output is correct
29 Correct 138 ms 35404 KB Output is correct
30 Correct 133 ms 35412 KB Output is correct
31 Correct 149 ms 35940 KB Output is correct
32 Correct 165 ms 40412 KB Output is correct