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Submission #934528

# Submission time Handle Problem Language Result Execution time Memory
934528 2024-02-27T13:58:53 Z a_l_i_r_e_z_a One-Way Streets (CEOI17_oneway) C++17
100 / 100
 66 ms 23320 KB 
// In the name of God
// Hope is last to die

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define pb push_back
// #define int long long
#define S second
#define F first
#define mp make_pair
#define smax(x, y) (x) = max((x), (y))
#define smin(x, y) (x) = min((x), (y))
#define all(x) (x).begin(), (x).end()
#define len(x) ((int)(x).size())

const int maxn = 1e5 + 5;
const int inf = 1e9 + 7;
int n, m, p, h[maxn], dp[maxn], sz[maxn], par[maxn], val[maxn];
vector<pair<int, pii>> adj[maxn], g[maxn];
pii ed[maxn];
char ans[maxn];
bool mark[maxn], cut[maxn];

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

void merge(int u, int v){
    u = find(u);
    v = find(v);
    if(u == v) return;
    if(sz[u] > sz[v]) swap(u, v);
    par[u] = v;
    sz[v] += sz[u];
}

void dfs_cut(int v, int p){
    dp[v] = h[v];
    mark[v] = 1;
    for(auto [u, e]: adj[v]){
        if(p == e.F) continue;
        if(!mark[u]){
            h[u] = h[v] + 1;
            dfs_cut(u, e.F);
            if(dp[u] > h[v]) cut[e.F] = 1;
        }
        smin(dp[v], dp[u]);
    }
}

void dfs(int v, int p = -1, int pe = -1, int d = -1){
    mark[v] = 1;
    for(auto [u, e]: g[v]){
        if(u == p) continue;
        dfs(u, v, e.F, e.S);
        val[v] += val[u];
    }
    if(p == -1) return;
    if(val[v] == 0){
        ans[pe] = 'B';
        return;
    }
    if(val[v] < 0){
        if(d == 1) ans[pe] = 'R';
        else ans[pe] = 'L';
    }
    else{
        if(d == 0) ans[pe] = 'R';
        else ans[pe] = 'L';
    }
}

int32_t main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n >> m;
    for(int i = 1; i <= n; i++){
        par[i] = i;
        sz[i] = 1;
    }
    for(int i = 0; i < m; i++){
        int u, v; cin >> u >> v;
        adj[u].pb(mp(v, mp(i, 1)));
        adj[v].pb(mp(u, mp(i, 0)));
        ed[i] = mp(u, v);
    }
    for(int i = 1; i <= n; i++){
        if(!mark[i]) dfs_cut(i, -1);
    }
    for(int i = 0; i < m; i++){
        if(cut[i]) continue;
        ans[i] = 'B';
        merge(ed[i].F, ed[i].S);
    }
    for(int i = 0; i < m; i++){
        if(!cut[i]) continue;
        int v = find(ed[i].F), u = find(ed[i].S);
        g[v].pb(mp(u, mp(i, 1)));
        g[u].pb(mp(v, mp(i, 0)));
    }
    cin >> p;
    for(int i = 0; i < p; i++){
        int u, v; cin >> u >> v;
        u = find(u), v = find(v);
        val[u]++;
        val[v]--;
    }
    fill(mark + 1, mark + n + 1, 0);
    for(int i = 1; i <= n; i++){
        if(!mark[find(i)]) dfs(find(i));
    }
    for(int i = 0; i < m; i++) cout << ans[i];

    return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 2 ms 6748 KB Output is correct
5 Correct 2 ms 6748 KB Output is correct
6 Correct 2 ms 6492 KB Output is correct
7 Correct 2 ms 6748 KB Output is correct
8 Correct 2 ms 6748 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 2 ms 6492 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 2 ms 6748 KB Output is correct
5 Correct 2 ms 6748 KB Output is correct
6 Correct 2 ms 6492 KB Output is correct
7 Correct 2 ms 6748 KB Output is correct
8 Correct 2 ms 6748 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 2 ms 6492 KB Output is correct
11 Correct 28 ms 13148 KB Output is correct
12 Correct 30 ms 13908 KB Output is correct
13 Correct 31 ms 14928 KB Output is correct
14 Correct 38 ms 16212 KB Output is correct
15 Correct 45 ms 16724 KB Output is correct
16 Correct 48 ms 17912 KB Output is correct
17 Correct 45 ms 19024 KB Output is correct
18 Correct 42 ms 17744 KB Output is correct
19 Correct 47 ms 19964 KB Output is correct
20 Correct 30 ms 13392 KB Output is correct
21 Correct 27 ms 13148 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 2 ms 6492 KB Output is correct
4 Correct 2 ms 6748 KB Output is correct
5 Correct 2 ms 6748 KB Output is correct
6 Correct 2 ms 6492 KB Output is correct
7 Correct 2 ms 6748 KB Output is correct
8 Correct 2 ms 6748 KB Output is correct
9 Correct 1 ms 6492 KB Output is correct
10 Correct 2 ms 6492 KB Output is correct
11 Correct 28 ms 13148 KB Output is correct
12 Correct 30 ms 13908 KB Output is correct
13 Correct 31 ms 14928 KB Output is correct
14 Correct 38 ms 16212 KB Output is correct
15 Correct 45 ms 16724 KB Output is correct
16 Correct 48 ms 17912 KB Output is correct
17 Correct 45 ms 19024 KB Output is correct
18 Correct 42 ms 17744 KB Output is correct
19 Correct 47 ms 19964 KB Output is correct
20 Correct 30 ms 13392 KB Output is correct
21 Correct 27 ms 13148 KB Output is correct
22 Correct 57 ms 20048 KB Output is correct
23 Correct 65 ms 18512 KB Output is correct
24 Correct 66 ms 18860 KB Output is correct
25 Correct 63 ms 23320 KB Output is correct
26 Correct 65 ms 19792 KB Output is correct
27 Correct 58 ms 18592 KB Output is correct
28 Correct 23 ms 10840 KB Output is correct
29 Correct 43 ms 14088 KB Output is correct
30 Correct 41 ms 14160 KB Output is correct
31 Correct 40 ms 14420 KB Output is correct
32 Correct 47 ms 17352 KB Output is correct