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Submission #259213

# Submission time Handle Problem Language Result Execution time Memory
259213 2020-08-07T12:06:20 Z dolphingarlic One-Way Streets (CEOI17_oneway) C++14
100 / 100
 159 ms 21336 KB 
#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
 
vector<pair<int, int>> graph[100001], compressed[100001];
pair<int, int> edges[100001];
bool visited[100001], bidir[100001], to_right[100001];
int tin[100001], tout[100001], low[100001], timer;
int cmp[100001], bit[100001];
 
int find(int A) {
    while (cmp[A] != A) cmp[A] = cmp[cmp[A]], A = cmp[A];
    return A;
}
void onion(int A, int B) {
    cmp[find(A)] = find(B);
}
 
void bridge_dfs(int node, int parent = 0) {
    visited[node] = true;
    tin[node] = low[node] = ++timer;
    for (pair<int, int> i : graph[node]) if (i.second != parent) {
        if (visited[i.first]) low[node] = min(low[node], tin[i.first]);
        else {
            bridge_dfs(i.first, i.second);
            low[node] = min(low[node], low[i.first]);
            if (low[i.first] > tin[node]) bidir[i.second] = true;
        }
    }
}
 
void ett_dfs(int node, int parent = 0) {
    visited[node] = true;
    tin[node] = ++timer;
    for (pair<int, int> i : compressed[node]) if (i.first != parent) {
        ett_dfs(i.first, node);
    }
    tout[node] = timer;
}
 
void update(int pos, int val) {
    for (; pos <= timer; pos += (pos & (-pos))) bit[pos] += val;
}
int query(int a, int b) {
    int ans = 0;
    for (; b; b -= (b & (-b))) ans += bit[b];
    for (a--; a; a -= (a & -a)) ans -= bit[a];
    return ans;
}
 
void dir_dfs(int node, int parent = 0) {
    visited[node] = true;
    for (pair<int, int> i : compressed[node]) if (i.first != parent) {
        int weight = query(tin[i.first], tout[i.first]);
        if (!weight) bidir[abs(i.second)] = false;
        else if (weight < 0) to_right[abs(i.second)] = i.second > 0;
        else to_right[abs(i.second)] = i.second < 0;
        dir_dfs(i.first, node);
    }
}
 
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    iota(cmp + 1, cmp + n + 1, 1);
    for (int i = 1; i <= m; i++) {
        int u, v;
        cin >> u >> v;
        graph[u].push_back({v, i});
        graph[v].push_back({u, i});
        edges[i] = {u, v};
    }
    timer = 0;
    for (int i = 1; i <= n; i++) if (!visited[i]) bridge_dfs(i);
    for (int i = 1; i <= m; i++) if (!bidir[i]) onion(edges[i].first, edges[i].second);
    for (int i = 1; i <= m; i++) if (bidir[i]) {
        compressed[find(edges[i].first)].push_back({find(edges[i].second), i});
        compressed[find(edges[i].second)].push_back({find(edges[i].first), -i});
    }
    timer = 0;
    memset(visited, 0, sizeof visited);
    for (int i = 1; i <= n; i++) if (!visited[find(i)]) ett_dfs(find(i));
 
    int p;
    cin >> p;
    while (p--) {
        int a, b;
        cin >> a >> b;
        update(tin[find(a)], 1);
        update(tin[find(b)], -1);
    }
 
    memset(visited, 0, sizeof visited);
    for (int i = 1; i <= n; i++) if (!visited[find(i)]) dir_dfs(find(i));
    for (int i = 1; i <= m; i++) {
        cout << (bidir[i] ? (to_right[i] ? 'R' : 'L') : 'B');
    }
    return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5120 KB Output is correct
2 Correct 4 ms 5120 KB Output is correct
3 Correct 4 ms 5248 KB Output is correct
4 Correct 5 ms 5248 KB Output is correct
5 Correct 4 ms 5248 KB Output is correct
6 Correct 4 ms 5248 KB Output is correct
7 Correct 4 ms 5248 KB Output is correct
8 Correct 6 ms 5248 KB Output is correct
9 Correct 5 ms 5280 KB Output is correct
10 Correct 4 ms 5248 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5120 KB Output is correct
2 Correct 4 ms 5120 KB Output is correct
3 Correct 4 ms 5248 KB Output is correct
4 Correct 5 ms 5248 KB Output is correct
5 Correct 4 ms 5248 KB Output is correct
6 Correct 4 ms 5248 KB Output is correct
7 Correct 4 ms 5248 KB Output is correct
8 Correct 6 ms 5248 KB Output is correct
9 Correct 5 ms 5280 KB Output is correct
10 Correct 4 ms 5248 KB Output is correct
11 Correct 58 ms 11000 KB Output is correct
12 Correct 54 ms 12024 KB Output is correct
13 Correct 69 ms 13128 KB Output is correct
14 Correct 91 ms 14584 KB Output is correct
15 Correct 90 ms 15092 KB Output is correct
16 Correct 122 ms 16504 KB Output is correct
17 Correct 100 ms 17784 KB Output is correct
18 Correct 130 ms 16804 KB Output is correct
19 Correct 92 ms 18680 KB Output is correct
20 Correct 60 ms 11640 KB Output is correct
21 Correct 50 ms 11768 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5120 KB Output is correct
2 Correct 4 ms 5120 KB Output is correct
3 Correct 4 ms 5248 KB Output is correct
4 Correct 5 ms 5248 KB Output is correct
5 Correct 4 ms 5248 KB Output is correct
6 Correct 4 ms 5248 KB Output is correct
7 Correct 4 ms 5248 KB Output is correct
8 Correct 6 ms 5248 KB Output is correct
9 Correct 5 ms 5280 KB Output is correct
10 Correct 4 ms 5248 KB Output is correct
11 Correct 58 ms 11000 KB Output is correct
12 Correct 54 ms 12024 KB Output is correct
13 Correct 69 ms 13128 KB Output is correct
14 Correct 91 ms 14584 KB Output is correct
15 Correct 90 ms 15092 KB Output is correct
16 Correct 122 ms 16504 KB Output is correct
17 Correct 100 ms 17784 KB Output is correct
18 Correct 130 ms 16804 KB Output is correct
19 Correct 92 ms 18680 KB Output is correct
20 Correct 60 ms 11640 KB Output is correct
21 Correct 50 ms 11768 KB Output is correct
22 Correct 139 ms 19064 KB Output is correct
23 Correct 130 ms 17784 KB Output is correct
24 Correct 159 ms 17976 KB Output is correct
25 Correct 124 ms 21336 KB Output is correct
26 Correct 121 ms 18588 KB Output is correct
27 Correct 136 ms 17784 KB Output is correct
28 Correct 40 ms 9208 KB Output is correct
29 Correct 84 ms 12532 KB Output is correct
30 Correct 80 ms 12792 KB Output is correct
31 Correct 81 ms 12792 KB Output is correct
32 Correct 110 ms 15736 KB Output is correct