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Submission #938283

# Submission time Handle Problem Language Result Execution time Memory
938283 2024-03-05T04:08:35 Z vjudge1 One-Way Streets (CEOI17_oneway) C++17
100 / 100
 265 ms 63400 KB 
#include <bits/stdc++.h>

using namespace std;

#define all(x) x.begin(), x.end()
#define ar array
#define pb push_back
#define ln '\n'
#define int long long

using i64 = long long;

template <class F, class _S>
bool chmin(F &u, const _S &v){
    bool flag = false;
    if ( u > v ){
        u = v; flag |= true;
    }
    return flag;
}

template <class F, class _S>
bool chmax(F &u, const _S &v){
    bool flag = false;
    if ( u < v ){
        u = v; flag |= true;
    }
    return flag;
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m; cin >> n >> m;
    vector <vector<ar<int,2>>> adj(n);
    vector <ar<int,2>> E;
    map <int,map<int,int>> mp;
    for ( int i = 0; i < m; i++ ){
        int u, v; cin >> u >> v;
        --u, --v;
        adj[u].pb({v, i});
        adj[v].pb({u, i});
        E.pb({u, v});
        mp[u][v]++;
        mp[v][u]++;
    }
    int p; cin >> p;
    vector <vector<ar<int,2>>> q(n);
    for ( int i = 0; i < p; i++ ){
        int x, y; cin >> x >> y;
        --x, --y;
        q[x].pb({y, 0});
        q[y].pb({x, 1});
    }
    vector <int> us(n), tin(n), tout(n), dir(m);
    int ct = 0;
    auto trav = [&](auto trav, int u, int p) -> void{
        us[u] = true;
        tin[u] = ++ct;
        for ( auto &[v, j]: adj[u] ){
            if ( v != p && !us[v] ){
                if ( E[j] == ar<int,2>{u, v} ){
                    dir[j] = 1;
                }
                trav(trav, v, u);
            }
        } tout[u] = ct;
    };
    vector <int> roots;
    for ( int i = 0; i < n; i++ ){
        if ( !us[i] ){
            roots.pb(i);
            trav(trav, i, -1);
        }
    }
    vector <int> low(n), ans(m, -1);
    vector <pair<int,int>> mn(n), mx(n);
    auto dfs = [&](auto dfs, int u, int p) -> void{
        mn[u] = {n + 1, -1};
        mx[u] = {0, -1};
        for ( auto &[v, t]: q[u] ){
            chmin(mn[u], pair<int,int>{tin[v], t});
            chmax(mx[u], pair<int,int>{tout[v], t});
        }
        low[u] = tin[u];
        vector <ar<int,2>> tmp;
        for ( auto &[v, j]: adj[u] ){
            if ( v != p ){
                if ( low[v] ){
                    chmin(low[u], tin[v]);
                } else{
                    dfs(dfs, v, u);
                    chmin(mn[u], mn[v]);
                    chmax(mx[u], mx[v]);
                    chmin(low[u], low[v]);
                    if ( low[v] > tin[u] ){
                        tmp.pb({v, j});
                    }
                }
            }
        }
        for ( auto &[v, j]: tmp ){
            if ( mn[v].first < tin[v] ){
                ans[j] = mn[v].second;
            }
            if ( mx[v].first > tout[v] ){
                ans[j] = mx[v].second;
            }
        }
    };
    for ( auto &u: roots ){
        dfs(dfs, u, -1);
    }
    for ( int i = 0; i < m; i++ ){
        auto [u, v] = E[i];
        if ( mp[u][v] > 1 ){
            ans[i] = -1;
        }
    }
    int it = 0;
    for ( auto &x: ans ){
        x ^= dir[it++];
        cout << (x > 0 ? 'L' : x < 0 ? 'B' : 'R');
    }

    cout << '\n';
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 860 KB Output is correct
4 Correct 1 ms 860 KB Output is correct
5 Correct 1 ms 860 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 860 KB Output is correct
8 Correct 1 ms 860 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 1 ms 604 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 860 KB Output is correct
4 Correct 1 ms 860 KB Output is correct
5 Correct 1 ms 860 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 860 KB Output is correct
8 Correct 1 ms 860 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 1 ms 604 KB Output is correct
11 Correct 149 ms 29364 KB Output is correct
12 Correct 170 ms 33760 KB Output is correct
13 Correct 192 ms 39376 KB Output is correct
14 Correct 226 ms 45508 KB Output is correct
15 Correct 232 ms 46784 KB Output is correct
16 Correct 228 ms 42688 KB Output is correct
17 Correct 195 ms 48068 KB Output is correct
18 Correct 229 ms 42688 KB Output is correct
19 Correct 178 ms 51504 KB Output is correct
20 Correct 171 ms 36060 KB Output is correct
21 Correct 131 ms 34568 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 860 KB Output is correct
4 Correct 1 ms 860 KB Output is correct
5 Correct 1 ms 860 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 860 KB Output is correct
8 Correct 1 ms 860 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 1 ms 604 KB Output is correct
11 Correct 149 ms 29364 KB Output is correct
12 Correct 170 ms 33760 KB Output is correct
13 Correct 192 ms 39376 KB Output is correct
14 Correct 226 ms 45508 KB Output is correct
15 Correct 232 ms 46784 KB Output is correct
16 Correct 228 ms 42688 KB Output is correct
17 Correct 195 ms 48068 KB Output is correct
18 Correct 229 ms 42688 KB Output is correct
19 Correct 178 ms 51504 KB Output is correct
20 Correct 171 ms 36060 KB Output is correct
21 Correct 131 ms 34568 KB Output is correct
22 Correct 228 ms 54252 KB Output is correct
23 Correct 235 ms 49848 KB Output is correct
24 Correct 265 ms 49088 KB Output is correct
25 Correct 215 ms 63400 KB Output is correct
26 Correct 230 ms 53032 KB Output is correct
27 Correct 221 ms 49604 KB Output is correct
28 Correct 59 ms 13048 KB Output is correct
29 Correct 189 ms 41100 KB Output is correct
30 Correct 173 ms 41576 KB Output is correct
31 Correct 191 ms 42436 KB Output is correct
32 Correct 168 ms 47040 KB Output is correct