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Submission #312876

# Submission time Handle Problem Language Result Execution time Memory
312876 2020-10-14T14:21:10 Z two_sides One-Way Streets (CEOI17_oneway) C++17
100 / 100
 335 ms 22136 KB 
#include <bits/stdc++.h>
using namespace std;

#define eb emplace_back
#define fi first
#define se second

struct edge {
    int u, v;
};

using ii = pair <int, int>;

const int N = 1e5 + 5;
const int LG = 18;

int col[N], bri[N], pred[N];
int num[N], low[N], tim;
int par[N], p[LG][N], d[N];
vector <ii> adj[N]; edge ed[N];

int find_set(int u) {
    return u == par[u] ?
    u : par[u] = find_set(par[u]);
}

void dfs(int u) {
    int v, i;
    num[u] = low[u] = ++tim;
    for (ii pp : adj[u]) {
        tie(v, i) = pp;
        if (v == u) continue;
        if (num[v]) {
            if (p[0][v] == u) bri[v] = 0;
            if (v != p[0][u])
                low[u] = min(low[u], num[v]);
        }
        else {
            d[v] = d[u] + 1; pred[v] = i;
            p[0][v] = u; dfs(v);
            low[u] = min(low[u], low[v]);
            if (low[v] > num[u])
                bri[v] = 1;
        }
    }
}

int lca(int u, int v) {
    if (d[u] < d[v]) swap(u, v);
    for (int k = LG - 1; ~k; k--)
        if (d[p[k][u]] >= d[v])
            u = p[k][u];
    if (u == v) return u;
    for (int k = LG - 1; ~k; k--)
        if (p[k][u] != p[k][v]) {
            u = p[k][u]; v = p[k][v];
        }
    return p[0][u];
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(nullptr);
    int n, m; cin >> n >> m;
    for (int i = 0; i < m; i++) {
        cin >> ed[i].u >> ed[i].v;
        adj[ed[i].u].eb(ed[i].v, i);
        adj[ed[i].v].eb(ed[i].u, i);
    }
    iota(par + 1, par + n + 1, 1);
    for (int i = 1; i <= n; i++)
        if (!num[i]) dfs(i);
    for (int k = 1; k < LG; k++)
        for (int i = 1; i <= n; i++)
            p[k][i] = p[k - 1][p[k - 1][i]];
    int q; cin >> q;
    while (q--) {
        int u, v; cin >> u >> v;
        int r = lca(u, v);
        u = find_set(u);
        while (d[u] > d[r]) {
            if (bri[u]) col[pred[u]] = -1;
            par[u] = p[0][u];
            u = find_set(u);
        }
        v = find_set(v);
        while (d[v] > d[r]) {
            if (bri[v]) col[pred[v]] = 1;
            par[v] = p[0][v];
            v = find_set(v);
        }
    }
    for (int i = 1; i <= n; i++)
        if (bri[i] && ed[pred[i]].v != i)
            col[pred[i]] *= -1;
    for (int i = 0; i < m; i++) {
        if (!col[i]) cout << 'B';
        if (col[i] == 1) cout << 'R';
        if (col[i] == -1) cout << 'L';
    }
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2816 KB Output is correct
2 Correct 2 ms 2816 KB Output is correct
3 Correct 3 ms 2944 KB Output is correct
4 Correct 3 ms 2944 KB Output is correct
5 Correct 3 ms 2944 KB Output is correct
6 Correct 3 ms 2944 KB Output is correct
7 Correct 3 ms 2944 KB Output is correct
8 Correct 3 ms 2944 KB Output is correct
9 Correct 3 ms 2944 KB Output is correct
10 Correct 2 ms 2816 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2816 KB Output is correct
2 Correct 2 ms 2816 KB Output is correct
3 Correct 3 ms 2944 KB Output is correct
4 Correct 3 ms 2944 KB Output is correct
5 Correct 3 ms 2944 KB Output is correct
6 Correct 3 ms 2944 KB Output is correct
7 Correct 3 ms 2944 KB Output is correct
8 Correct 3 ms 2944 KB Output is correct
9 Correct 3 ms 2944 KB Output is correct
10 Correct 2 ms 2816 KB Output is correct
11 Correct 44 ms 9848 KB Output is correct
12 Correct 56 ms 11896 KB Output is correct
13 Correct 62 ms 14456 KB Output is correct
14 Correct 82 ms 17784 KB Output is correct
15 Correct 81 ms 18424 KB Output is correct
16 Correct 75 ms 18296 KB Output is correct
17 Correct 69 ms 19192 KB Output is correct
18 Correct 75 ms 18296 KB Output is correct
19 Correct 69 ms 19884 KB Output is correct
20 Correct 54 ms 12844 KB Output is correct
21 Correct 58 ms 13184 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2816 KB Output is correct
2 Correct 2 ms 2816 KB Output is correct
3 Correct 3 ms 2944 KB Output is correct
4 Correct 3 ms 2944 KB Output is correct
5 Correct 3 ms 2944 KB Output is correct
6 Correct 3 ms 2944 KB Output is correct
7 Correct 3 ms 2944 KB Output is correct
8 Correct 3 ms 2944 KB Output is correct
9 Correct 3 ms 2944 KB Output is correct
10 Correct 2 ms 2816 KB Output is correct
11 Correct 44 ms 9848 KB Output is correct
12 Correct 56 ms 11896 KB Output is correct
13 Correct 62 ms 14456 KB Output is correct
14 Correct 82 ms 17784 KB Output is correct
15 Correct 81 ms 18424 KB Output is correct
16 Correct 75 ms 18296 KB Output is correct
17 Correct 69 ms 19192 KB Output is correct
18 Correct 75 ms 18296 KB Output is correct
19 Correct 69 ms 19884 KB Output is correct
20 Correct 54 ms 12844 KB Output is correct
21 Correct 58 ms 13184 KB Output is correct
22 Correct 335 ms 20344 KB Output is correct
23 Correct 289 ms 19448 KB Output is correct
24 Correct 288 ms 19448 KB Output is correct
25 Correct 268 ms 22136 KB Output is correct
26 Correct 285 ms 20064 KB Output is correct
27 Correct 262 ms 19320 KB Output is correct
28 Correct 50 ms 6904 KB Output is correct
29 Correct 162 ms 13840 KB Output is correct
30 Correct 159 ms 14344 KB Output is correct
31 Correct 154 ms 14072 KB Output is correct
32 Correct 194 ms 17016 KB Output is correct