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Submission #1106161

# Submission time Handle Problem Language Result Execution time Memory
1106161 2024-10-29T11:55:20 Z PagodePaiva One-Way Streets (CEOI17_oneway) C++17
100 / 100
 522 ms 59388 KB 
#include<bits/stdc++.h>

using namespace std;

const int N = 100010;

vector <pair <int, int>> g[N];
vector <pair <int, int>> backedges[N];
int l[N], r[N];
int mark[N];
set <array <int, 3>> edges;
vector <array <int, 3>> arestas;
int tin[N], low[N], pai[N];
int tmm = 1;
char res[N];
map <pair <int,int>, int> look;
int aux[N];
int sz[N];

void dfs3(int v, int p){
    int val = -1;
    aux[v] = 1;
    sz[v] = l[v]-r[v];
    for(auto [x, i] : g[v]){
        if(x == p){
            val = i;
            look[{x, v}] = look[{v, x}] = i;
            continue; 
        }
        dfs3(x, v);
        sz[v] += sz[x];
    }
    if(val == -1) return;
    if(res[val] == 'B') return;
    if(sz[v] == 0){
        res[val] = 'B';
    }
    else if(sz[v] > 0){
        res[val] = 'U';
    }
    else{
        res[val] = 'D';
    }
}

void dfs2(int v, int p){
    pai[v] = p;
    tin[v] = tmm;
    tmm++;
    low[v] = tin[v];
    for(auto [x,i] : backedges[v]){
        if(tin[x] == 0) continue;
        low[v] = min(low[v], tin[x]);
    }
    for(auto [x,i] : g[v]){
        if(x == p) {
            look[{x, v}] = look[{v, x}] = i;
            continue;
        }
        dfs2(x,v);
        low[v] = min(low[v], low[x]);
    }
    tmm++;
    return;
}

void dfs(int v, int p){
    mark[v] = 1;
    for(auto [x, i] : g[v]){
        if(x == p) continue;
        if(mark[x] == 1) continue;
        edges.insert({v, x, i});
        edges.insert({x, v, i});
        dfs(x, v);
    }
    return;
}

map <pair <int, int>, int> buceta;

int main(){
    int n, m;
    cin >> n >> m;
    for(int i = 0;i < m;i++){
        int a, b;
        cin >> a >> b;
        g[a].push_back({b, i});
        g[b].push_back({a, i});
        arestas.push_back({a, b, i});
        look[{a, b}] = i;
        look[{b, a}] = i;
        buceta[{a, b}] = 0;
        buceta[{b, a}] = 1;
    }
    int q;
    cin >> q;
    while(q--){
        int a, b;cin >> a >> b;
        l[a]++;
        r[b]++;
    }
    for(int i = 1;i <= n;i++){
        if(mark[i] == 0) dfs(i, i);
    }
    for(int i = 1;i <= n;i++) g[i].clear();
    for(auto [a, b, i] : edges){
        g[a].push_back({b, i});
    }
    for(auto [a, b, i] : arestas){
        if(edges.find({a, b, i}) != edges.end() or edges.find({b, a, i}) != edges.end()) continue;
        backedges[a].push_back({b, i});
        backedges[b].push_back({a, i});
        res[i] = 'B';
    }
    for(int i = 1;i <= n;i++){
        if(pai[i] == 0){
            dfs2(i, i);
        }
    }
    for(int i = 1;i <= n;i++){
        if(i == pai[i]) continue;
        if(low[i] <= tin[pai[i]]){
            int t = look[{i, pai[i]}];
            res[t] = 'B';
        } 
    }
    for(int i = 1;i <= n;i++){
        if(aux[i] == 0) dfs3(i, i);
    }
    for(int i = 1;i <= n;i++){
        if(i == pai[i]) continue;
        int val = look[{i, pai[i]}];
        if(res[val] == 'B') continue;   
        if(buceta[{i, pai[i]}] == 0){
            if(res[val] == 'U') res[val] = 'R';
            else res[val] = 'L';
        }
        else{
            if(res[val] == 'U') res[val] = 'L';
            else res[val] = 'R';
        }
    }
    //cout << m << '\n';
    for(int i = 0;i < m;i++){
        cout << res[i];
        if(res[i] != 'B' and res[i] != 'L' and res[i] != 'R') return 1;
    }
    cout << '\n';
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 8016 KB Output is correct
2 Correct 2 ms 8016 KB Output is correct
3 Correct 4 ms 8548 KB Output is correct
4 Correct 4 ms 8528 KB Output is correct
5 Correct 4 ms 8696 KB Output is correct
6 Correct 4 ms 8272 KB Output is correct
7 Correct 5 ms 8528 KB Output is correct
8 Correct 5 ms 8528 KB Output is correct
9 Correct 4 ms 8528 KB Output is correct
10 Correct 4 ms 8528 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 8016 KB Output is correct
2 Correct 2 ms 8016 KB Output is correct
3 Correct 4 ms 8548 KB Output is correct
4 Correct 4 ms 8528 KB Output is correct
5 Correct 4 ms 8696 KB Output is correct
6 Correct 4 ms 8272 KB Output is correct
7 Correct 5 ms 8528 KB Output is correct
8 Correct 5 ms 8528 KB Output is correct
9 Correct 4 ms 8528 KB Output is correct
10 Correct 4 ms 8528 KB Output is correct
11 Correct 316 ms 44576 KB Output is correct
12 Correct 344 ms 46588 KB Output is correct
13 Correct 355 ms 49632 KB Output is correct
14 Correct 435 ms 52552 KB Output is correct
15 Correct 451 ms 52988 KB Output is correct
16 Correct 468 ms 51964 KB Output is correct
17 Correct 392 ms 54276 KB Output is correct
18 Correct 430 ms 51964 KB Output is correct
19 Correct 393 ms 55804 KB Output is correct
20 Correct 353 ms 48380 KB Output is correct
21 Correct 291 ms 46588 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 8016 KB Output is correct
2 Correct 2 ms 8016 KB Output is correct
3 Correct 4 ms 8548 KB Output is correct
4 Correct 4 ms 8528 KB Output is correct
5 Correct 4 ms 8696 KB Output is correct
6 Correct 4 ms 8272 KB Output is correct
7 Correct 5 ms 8528 KB Output is correct
8 Correct 5 ms 8528 KB Output is correct
9 Correct 4 ms 8528 KB Output is correct
10 Correct 4 ms 8528 KB Output is correct
11 Correct 316 ms 44576 KB Output is correct
12 Correct 344 ms 46588 KB Output is correct
13 Correct 355 ms 49632 KB Output is correct
14 Correct 435 ms 52552 KB Output is correct
15 Correct 451 ms 52988 KB Output is correct
16 Correct 468 ms 51964 KB Output is correct
17 Correct 392 ms 54276 KB Output is correct
18 Correct 430 ms 51964 KB Output is correct
19 Correct 393 ms 55804 KB Output is correct
20 Correct 353 ms 48380 KB Output is correct
21 Correct 291 ms 46588 KB Output is correct
22 Correct 466 ms 55304 KB Output is correct
23 Correct 437 ms 52992 KB Output is correct
24 Correct 501 ms 53164 KB Output is correct
25 Correct 491 ms 59388 KB Output is correct
26 Correct 455 ms 54864 KB Output is correct
27 Correct 522 ms 53248 KB Output is correct
28 Correct 109 ms 15612 KB Output is correct
29 Correct 371 ms 48752 KB Output is correct
30 Correct 379 ms 48748 KB Output is correct
31 Correct 393 ms 49464 KB Output is correct
32 Correct 350 ms 47256 KB Output is correct