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Submission #1027348

# Submission time Handle Problem Language Result Execution time Memory
1027348 2024-07-19T03:53:44 Z khanhphucscratch One-Way Streets (CEOI17_oneway) C++14
100 / 100
 233 ms 44228 KB 
#include<bits/stdc++.h>
using namespace std;
set<pair<int, int>> edges;
map<pair<int, int>, int> f;
map<pair<int, int>, pair<int, int>> edge_tree_to_graph;
vector<pair<int, int>> bridges;
vector<int> ad[100005], ad2[100005];
int low[100005], num[100005], c[100005], dp[100005], ans[100005], dfsc = 0, color = 0;
//0 = B; 1 = L; 2 = R;
bool visited[100005];
inline pair<int, int> edgeCorrection(pair<int, int> x)
{
    if(edges.count(x) == 0) swap(x.first, x.second);
    return x;
}
void dfs(int u, int par)
{
    low[u] = num[u] = ++dfsc;
    bool avoidpar = 1;
    for(int v : ad[u]){
        if(v != par || avoidpar == 0){
            if(num[v] > 0) low[u] = min(low[u], num[v]);
            else{
                dfs(v, u);
                low[u] = min(low[u], low[v]);
            }
        }
        else avoidpar = 0;
    }
}
void dfscolor(int u, int co)
{
    //cout<<"A"<<u<<" "<<color<<endl;
    visited[u] = 1; c[u] = co;
    for(int v : ad[u]) if(visited[v] == 0){
        if(low[v] == num[v]){
            dfscolor(v, ++color);
            bridges.push_back(edgeCorrection({u, v}));
        }
        else dfscolor(v, co);
    }
}
void dfsdirect(int u)
{
    visited[u] = 1;
    for(int v : ad2[u]) if(visited[v] == 0){
        //if(u == c[4]) cout<<"B"<<v<<endl;
        dfsdirect(v); dp[u] += dp[v];
        if(dp[v] != 0){
            //if(v == c[4]) cout<<"B"<<u<<" "<<v<<endl;
            pair<int, int> thisedge = edge_tree_to_graph[{u, v}];
            if(dp[v] > 0){
                if(c[thisedge.first] == u) ans[f[thisedge]] = 1;
                else ans[f[thisedge]] = 2;
            }
            else{
                if(c[thisedge.first] == u) ans[f[thisedge]] = 2;
                else ans[f[thisedge]] = 1;
            }
        }
    }
    //cout<<u<<" "<<dp[u]<<endl;
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin>>n>>m;
    for(int i = 1; i <= m; i++){
        int u, v;
        cin>>u>>v;
        if(u == v) continue;
        ad[u].push_back(v);
        ad[v].push_back(u);
        edges.insert({u, v});
        f[{u, v}] = i;
    }
    for(int i = 1; i <= n; i++) if(num[i] == 0){
        dfs(i, -1);
        color++;
        dfscolor(i, color);
    }
    for(pair<int, int> i : bridges){
        ad2[c[i.first]].push_back(c[i.second]);
        ad2[c[i.second]].push_back(c[i.first]);
        edge_tree_to_graph[{c[i.first], c[i.second]}] = i;
        edge_tree_to_graph[{c[i.second], c[i.first]}] = i;
    }
    int p; cin>>p;
    for(int i = 1; i <= p; i++){
        int u, v;
        cin>>u>>v;
        dp[c[u]]++; dp[c[v]]--;
    }
    //cout<<"A"<<dp[c[4]]<<endl;
    memset(visited, 0, sizeof(visited));
    for(int i = 1; i <= color; i++) if(visited[i] == 0){
        dfsdirect(i);
    }
    for(int i = 1; i <= m; i++){
        if(ans[i] == 0) cout<<"B";
        else if(ans[i] == 1) cout<<"L";
        else cout<<"R";
    }
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 7004 KB Output is correct
2 Correct 1 ms 7004 KB Output is correct
3 Correct 2 ms 7260 KB Output is correct
4 Correct 3 ms 7264 KB Output is correct
5 Correct 2 ms 7260 KB Output is correct
6 Correct 2 ms 7000 KB Output is correct
7 Correct 2 ms 7260 KB Output is correct
8 Correct 2 ms 7260 KB Output is correct
9 Correct 3 ms 7260 KB Output is correct
10 Correct 2 ms 7260 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 7004 KB Output is correct
2 Correct 1 ms 7004 KB Output is correct
3 Correct 2 ms 7260 KB Output is correct
4 Correct 3 ms 7264 KB Output is correct
5 Correct 2 ms 7260 KB Output is correct
6 Correct 2 ms 7000 KB Output is correct
7 Correct 2 ms 7260 KB Output is correct
8 Correct 2 ms 7260 KB Output is correct
9 Correct 3 ms 7260 KB Output is correct
10 Correct 2 ms 7260 KB Output is correct
11 Correct 78 ms 20936 KB Output is correct
12 Correct 79 ms 21844 KB Output is correct
13 Correct 83 ms 23176 KB Output is correct
14 Correct 105 ms 26340 KB Output is correct
15 Correct 103 ms 27596 KB Output is correct
16 Correct 213 ms 37832 KB Output is correct
17 Correct 181 ms 40132 KB Output is correct
18 Correct 185 ms 38044 KB Output is correct
19 Correct 183 ms 41672 KB Output is correct
20 Correct 84 ms 21328 KB Output is correct
21 Correct 70 ms 20968 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 7004 KB Output is correct
2 Correct 1 ms 7004 KB Output is correct
3 Correct 2 ms 7260 KB Output is correct
4 Correct 3 ms 7264 KB Output is correct
5 Correct 2 ms 7260 KB Output is correct
6 Correct 2 ms 7000 KB Output is correct
7 Correct 2 ms 7260 KB Output is correct
8 Correct 2 ms 7260 KB Output is correct
9 Correct 3 ms 7260 KB Output is correct
10 Correct 2 ms 7260 KB Output is correct
11 Correct 78 ms 20936 KB Output is correct
12 Correct 79 ms 21844 KB Output is correct
13 Correct 83 ms 23176 KB Output is correct
14 Correct 105 ms 26340 KB Output is correct
15 Correct 103 ms 27596 KB Output is correct
16 Correct 213 ms 37832 KB Output is correct
17 Correct 181 ms 40132 KB Output is correct
18 Correct 185 ms 38044 KB Output is correct
19 Correct 183 ms 41672 KB Output is correct
20 Correct 84 ms 21328 KB Output is correct
21 Correct 70 ms 20968 KB Output is correct
22 Correct 224 ms 40140 KB Output is correct
23 Correct 193 ms 37832 KB Output is correct
24 Correct 202 ms 37960 KB Output is correct
25 Correct 187 ms 44228 KB Output is correct
26 Correct 200 ms 39620 KB Output is correct
27 Correct 233 ms 38068 KB Output is correct
28 Correct 40 ms 9304 KB Output is correct
29 Correct 93 ms 20896 KB Output is correct
30 Correct 80 ms 20936 KB Output is correct
31 Correct 90 ms 21384 KB Output is correct
32 Correct 127 ms 26800 KB Output is correct