oj.uz

Submission #1075055

# Submission time Handle Problem Language Result Execution time Memory
1075055 2024-08-25T17:58:50 Z pqthangv One-Way Streets (CEOI17_oneway) C++11
100 / 100
 80 ms 26452 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int INF = 1e9 + 5;
const ll oo = 1e18 + 5;

const int MAXN = 1e5 + 5;
const int LOG = 16;

#define int ll

int n, m, TimerDFS, low[MAXN], num[MAXN], scc_quanity, scc_id[MAXN], par[MAXN][LOG + 1];
int high[MAXN], f[MAXN];
pair<int, int> edges[MAXN];
vector<pair<int, int>> adj[MAXN];
vector<int> g[MAXN];
bool del[MAXN];
bool vis[MAXN];
stack<int> st;

void DFS_tarjan(int u, int pid) {
    ++TimerDFS;
    st.push(u);
//    cout << u << '\n';
    num[u] = low[u] = TimerDFS;
    for (int i = 0; i < int(adj[u].size()); ++i) {
        int v = adj[u][i].first, nid = adj[u][i].second;
        if (pid != nid && del[v] == false){
            if (num[v] == 0) {
                DFS_tarjan(v, nid);
                low[u] = min(low[u], low[v]);
            } else low[u] = min(low[u], num[v]);
        }
    }

    if (low[u] == num[u]) {
        int v;
        ++scc_quanity;
        do {
            v = st.top();
            del[v] = true;
            st.pop();
            scc_id[v] = scc_quanity;
        } while (v != u);
    }
}

//void DFS_high(int u, int p) {
//    for (int i = 0; i < int(g[u].size()); ++i) {
//        int v = g[u][i];
//        if (v != p) {
//            high[v] = high[u] + 1;
//            par[v][0] = u;
//            DFS_high(v, u);
//        }
//    }
//}

//void prepare_LCA() {
//    high[0] = -1;
//    DFS_high(1, -1);

//    for (int j = 1; j <= LOG; ++j) {
//        for (int i = 1; i <= n; ++i) {
//            par[i][j] = par[par[i][j - 1]][j - 1];
//        }
//    }
//}
//int LCA(int u, int v) {
//    if (high[u] < high[v]) return LCA(v, u);
//
//    int k = high[u] - high[v];
//
//    for (int i = 0; i <= LOG; ++i) {
//        if ((k >> i) & 1) {
//            u = par[u][i];
//        }
//    }
//
//    if (u == v) return u;
//
//    for (int i = LOG; i >= 0; --i) {
//        if (par[u][i] != par[v][i]) {
//            u = par[u][i];
//            v = par[v][i];
//        }
//    }
//    return par[u][0];
//}

void DFS_solve(int u, int p) {
    vis[u] = true;
    for (int i = 0; i < int(g[u].size()); ++i) {
        int v = g[u][i];
        if (v != p) {
            high[v] = high[u] + 1;
            if (!vis[v])
                DFS_solve(v, u);
            f[u] += f[v];
        }
    }
}

void solve()
{
    cin >> n >> m;
    for (int i = 1; i <= m; ++i) {
        int u, v; cin >> u >> v;
        adj[u].push_back({v, i});
        adj[v].push_back({u, i});
        edges[i] = {u, v};
    }
    for (int i = 1; i <= n; ++i)
        if (num[i] == 0) DFS_tarjan(i, -1);
//    cout << TimerDFS << '\n';
//    cout << scc_quanity << '\n';
//    for (int i = 1; i <= n; ++i) {
//        cout << scc_id[i] << ' ';
//    }
//    cout << '\n';

    for (int i = 1; i <= m; ++i) {
        int u = scc_id[edges[i].first], v = scc_id[edges[i].second];
        // vi la vo huong nen ko co canh trung
        if (u != v) {
            g[u].push_back(v);
            g[v].push_back(u);
        }
    }
//    for (int i = 1; i <= scc)
//    prepare_LCA();
    int q; cin >> q;
    while (q--) {
        int u, v; cin >> u >> v;
        u = scc_id[u];
        v = scc_id[v];
//        int uv = LCA(u, v);
        ++f[u];
        --f[v];
//        cout << u << ' ' << v << '\n';
//        f[uv] -= 3;
    }
    high[0] = -1;
    for (int i = 1; i <= scc_quanity; ++i)
        if (!vis[i])
            DFS_solve(i, -1);

    for (int i = 1; i <= m; ++i) {
        int u = scc_id[edges[i].first], v = scc_id[edges[i].second];
//        cout << u << ' ' << v << ' ' << high[u] << ' ' << high[v] << ' ' << f[u] << ' ' << f[v];
        if (u == v) {
            cout << "B";
        } else {
            if (high[u] > high[v]) {
                if (f[u] == 0) cout << "B";
                else
                if (f[u] >= 1) cout << "R";
                else cout << "L";
            } else if (f[v] == 0) cout << "B";
            else if (f[v] >= 1) cout << "L";
            else cout << "R";
        }
//        cout << '\n';
    }
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(NULL); cout.tie(NULL);

//    freopen("nhap.inp", "r", stdin);
//    freopen("khon.out", "w", stdout);

//    int T = 1; cin >> T; while(T--)
    solve();

    return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4952 KB Output is correct
2 Correct 3 ms 5212 KB Output is correct
3 Correct 2 ms 5212 KB Output is correct
4 Correct 2 ms 5212 KB Output is correct
5 Correct 3 ms 5212 KB Output is correct
6 Correct 2 ms 5212 KB Output is correct
7 Correct 2 ms 5212 KB Output is correct
8 Correct 3 ms 5212 KB Output is correct
9 Correct 4 ms 5180 KB Output is correct
10 Correct 3 ms 5208 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4952 KB Output is correct
2 Correct 3 ms 5212 KB Output is correct
3 Correct 2 ms 5212 KB Output is correct
4 Correct 2 ms 5212 KB Output is correct
5 Correct 3 ms 5212 KB Output is correct
6 Correct 2 ms 5212 KB Output is correct
7 Correct 2 ms 5212 KB Output is correct
8 Correct 3 ms 5212 KB Output is correct
9 Correct 4 ms 5180 KB Output is correct
10 Correct 3 ms 5208 KB Output is correct
11 Correct 27 ms 14540 KB Output is correct
12 Correct 33 ms 15704 KB Output is correct
13 Correct 37 ms 16976 KB Output is correct
14 Correct 41 ms 18512 KB Output is correct
15 Correct 56 ms 18988 KB Output is correct
16 Correct 49 ms 20816 KB Output is correct
17 Correct 50 ms 22384 KB Output is correct
18 Correct 64 ms 20764 KB Output is correct
19 Correct 57 ms 23296 KB Output is correct
20 Correct 36 ms 15444 KB Output is correct
21 Correct 35 ms 15148 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4952 KB Output is correct
2 Correct 3 ms 5212 KB Output is correct
3 Correct 2 ms 5212 KB Output is correct
4 Correct 2 ms 5212 KB Output is correct
5 Correct 3 ms 5212 KB Output is correct
6 Correct 2 ms 5212 KB Output is correct
7 Correct 2 ms 5212 KB Output is correct
8 Correct 3 ms 5212 KB Output is correct
9 Correct 4 ms 5180 KB Output is correct
10 Correct 3 ms 5208 KB Output is correct
11 Correct 27 ms 14540 KB Output is correct
12 Correct 33 ms 15704 KB Output is correct
13 Correct 37 ms 16976 KB Output is correct
14 Correct 41 ms 18512 KB Output is correct
15 Correct 56 ms 18988 KB Output is correct
16 Correct 49 ms 20816 KB Output is correct
17 Correct 50 ms 22384 KB Output is correct
18 Correct 64 ms 20764 KB Output is correct
19 Correct 57 ms 23296 KB Output is correct
20 Correct 36 ms 15444 KB Output is correct
21 Correct 35 ms 15148 KB Output is correct
22 Correct 62 ms 23376 KB Output is correct
23 Correct 70 ms 21884 KB Output is correct
24 Correct 80 ms 21884 KB Output is correct
25 Correct 59 ms 26452 KB Output is correct
26 Correct 66 ms 22924 KB Output is correct
27 Correct 72 ms 21836 KB Output is correct
28 Correct 22 ms 12092 KB Output is correct
29 Correct 46 ms 16136 KB Output is correct
30 Correct 59 ms 16268 KB Output is correct
31 Correct 45 ms 16748 KB Output is correct
32 Correct 56 ms 19656 KB Output is correct