oj.uz

Submission #878707

# Submission time Handle Problem Language Result Execution time Memory
878707 2023-11-25T06:02:20 Z Ghulam_Junaid One-Way Streets (CEOI17_oneway) C++17
0 / 100
 1 ms 2652 KB 
#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 10;
int n, m, p, h[N], mnh[N], st[N], ft[N], tme;

bool vis[N];
vector<pair<int, int>> g[N], edges, important;
string s;

bool in_sub(int u, int v){
    return (st[v] <= st[u] && st[u] < ft[v]);
}

void dfs(int v, int prev = -1){
    vis[v] = 1;
    mnh[v] = h[v];

    st[v] = tme;
    tme++;

    // cout << "Running dfs on " << v << endl;

    for (auto [id, u] : g[v]){
        if (id == prev) continue;

        if (!vis[u]){
            h[u] = h[v] + 1;
            dfs(u, id);
            mnh[v] = min(mnh[v], mnh[u]);

            if (mnh[u] == h[u]){ // (v, u) is a bridge
                // cout << v << " -- " << u << " is a bridge." << endl;
                for (auto [x, y] : important){
                    bool A = in_sub(x, u);
                    bool B = in_sub(y, u);

                    // cout << x << " " << y << " " << u << " " << A << " " << B << endl;

                    if (A and !B){
                        // u to v
                        if (edges[id].first == u)
                            s[id] = 'R';
                        else
                            s[id] = 'L';

                        break;
                    }
                    if (!A and B){
                        // v to u
                        if (edges[id].first == v)
                            s[id] = 'R';
                        else
                            s[id] = 'L';

                        break;
                    }
                }
            }
        }
        else{
            if (h[u] >= h[v]) continue;

            // u is an ancestor.
            mnh[v] = min(mnh[v], h[u]);
        }
    }
    ft[v] = tme;
}

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

    for (int i=0; i<m; i++){
        int u, v;
        cin >> u >> v;

        g[u].push_back({i, v});
        g[v].push_back({i, u});
        edges.push_back({u, v});

        s += 'B';
    }

    cin >> p;
    for (int i=0; i<p; i++){
        int u, v;
        cin >> u >> v;

        important.push_back({u, v});
    }

    dfs(1);

    cout << s << endl;
}

Subtask #1
0 / 30.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 2652 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 30.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 2652 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 40.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 2652 KB Output isn't correct
2 Halted 0 ms 0 KB -