oj.uz

Submission #904890

# Submission time Handle Problem Language Result Execution time Memory
904890 2024-01-12T10:48:09 Z selmahbn One-Way Streets (CEOI17_oneway) C++17
30 / 100
 345 ms 262144 KB 
#include <bits/stdc++.h>

using namespace std;

#define pii pair<int, int>

const int INF = numeric_limits<int>::max() / 2;

vector<int> num, low, comp, used;
stack<int> s;
int dfs_count = 0;
int comp_count = 0;

vector<vector<int>> dir;
vector<int> in;
vector<int> out;

void tarjan_dfs(int current, int parent, vector<vector<pii>>& adj) {
    num[current] = low[current] = dfs_count;
    dfs_count++;
    s.push(current);
    for (pii neigh : adj[current]) {
        if (used[neigh.second] == 1) continue;
        used[neigh.second] = 1;
        if (num[neigh.first] == INF) {
            tarjan_dfs(neigh.first, current, adj);
            low[current] = min(low[current], low[neigh.first]);
        } else low[current] = min(low[current], num[neigh.first]);
    }
    if (num[current] == low[current] && !s.empty()) {
        while (s.top() != current) {
            int top = s.top();
            s.pop();
            comp[top] = comp_count;
        }
        s.pop();
        comp[current] = comp_count;
        comp_count++;
    }
}

int dir_dfs(int current, vector<int>& visited, vector<vector<int>>& adj) {
    visited[current] = 1;
    int incoming = in[current] - out[current];
    for (int neigh : adj[current]) {
        if (visited[neigh] == 0) {
            int d = dir_dfs(neigh, visited, adj);
            if (d < 0) {
                dir[current][neigh] = -1;
                dir[neigh][current] = 1;
            } else if (d > 0) {
                dir[current][neigh] = 1;
                dir[neigh][current] = -1;
            }
            incoming += d;
        }
    }
    return incoming;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie();
    cout.tie();
    int n, m;
    cin >> n >> m;
    vector<vector<pii>> adj(n);
    vector<pii> streets;
    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        a--; b--;
        adj[a].push_back(make_pair(b, i));
        adj[b].push_back(make_pair(a, i));
        streets.push_back(make_pair(a, b));
    }
    num = vector<int>(n, INF);
    low = vector<int>(n);
    comp = vector<int>(n);
    used = vector<int>(m, 0);
    for (int i = 0; i < n; i++) {
        if (num[i] == INF) {
            tarjan_dfs(i, i, adj);
        }
    }
    vector<vector<int>> cadj(comp_count);
    for (pii s : streets) {
        if (comp[s.first] != comp[s.second]) {
            cadj[comp[s.first]].push_back(comp[s.second]);
            cadj[comp[s.second]].push_back(comp[s.first]);
        }
    }
    in = vector<int>(comp_count, 0);
    out = vector<int>(comp_count, 0);
    int p;
    cin >> p;
    for (int i = 0; i < p; i++) {
        int a, b;
        cin >> a >> b;
        a--; b--;
        if (comp[a] != comp[b]) {
            out[comp[a]]++;
            in[comp[b]]++;
        }
    }
    vector<int> visited(comp_count, 0);
    dir = vector<vector<int>>(comp_count, vector<int>(comp_count, 0));
    for (int i = 0; i < comp_count; i++) {
        if (visited[i] == 0) dir_dfs(i, visited, cadj);
    }
    for (pii s : streets) {
        if (comp[s.first] == comp[s.second] || dir[comp[s.first]][comp[s.second]] == 0) cout << 'B';
        else if (dir[comp[s.first]][comp[s.second]] == 1) cout << 'R';
        else cout << 'L';
    }
    return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 1 ms 344 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 2 ms 4444 KB Output is correct
5 Correct 3 ms 4444 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 3 ms 4444 KB Output is correct
8 Correct 3 ms 4444 KB Output is correct
9 Correct 1 ms 348 KB Output is correct
10 Correct 1 ms 348 KB Output is correct

Subtask #2
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 1 ms 344 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 2 ms 4444 KB Output is correct
5 Correct 3 ms 4444 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 3 ms 4444 KB Output is correct
8 Correct 3 ms 4444 KB Output is correct
9 Correct 1 ms 348 KB Output is correct
10 Correct 1 ms 348 KB Output is correct
11 Correct 30 ms 6348 KB Output is correct
12 Correct 32 ms 7880 KB Output is correct
13 Correct 83 ms 99528 KB Output is correct
14 Runtime error 345 ms 262144 KB Execution killed with signal 9
15 Halted 0 ms 0 KB -

Subtask #3
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 1 ms 344 KB Output is correct
3 Correct 1 ms 348 KB Output is correct
4 Correct 2 ms 4444 KB Output is correct
5 Correct 3 ms 4444 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 3 ms 4444 KB Output is correct
8 Correct 3 ms 4444 KB Output is correct
9 Correct 1 ms 348 KB Output is correct
10 Correct 1 ms 348 KB Output is correct
11 Correct 30 ms 6348 KB Output is correct
12 Correct 32 ms 7880 KB Output is correct
13 Correct 83 ms 99528 KB Output is correct
14 Runtime error 345 ms 262144 KB Execution killed with signal 9
15 Halted 0 ms 0 KB -