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Submission #866770

# Submission time Handle Problem Language Result Execution time Memory
866770 2023-10-27T03:20:29 Z _anhxinloi_ One-Way Streets (CEOI17_oneway) C++14
100 / 100
 61 ms 20572 KB 
#include<bits/stdc++.h>
#define int long long
#define fi first
#define se second

using namespace std;

const int maxn = 1e5 + 5;
const int inf = 1e18;
typedef pair<int, int> pii;

int low[maxn], num[maxn], tds, scc;
int lab[maxn], n, m, d[maxn], q;
char s[maxn];
stack<int> st;
vector<int> adj[maxn], g[maxn];
pii canh[maxn];
bool check[maxn];

void dfs(int u, int par)
{
    low[u] = num[u] = ++tds;
    st.push(u);
    int tds = 0;
    for(int v : adj[u]){
        if(v != par || tds == 1){
            if(num[v] != 0)
                low[u] = min(low[u], num[v]);
            else{
                dfs(v, u);
                low[u] = min(low[u], low[v]);
            }
        }
        else{
            tds++;
        }
    }

    if(low[u] >= num[u]){
        scc++;
        int tmp;
        do
        {
            tmp = st.top();
            st.pop();
            lab[tmp] = scc;
//            for (int w: adj[tmp]) {
//                if (lab[w] && scc != lab[w]){
//                    g[scc].push_back(lab[w]);
////                    cout << lab[w] << ' ' << scc << endl;
//                }
//            }
            low[tmp] = num[tmp] = inf;
        }while(tmp != u);
    }
}

void dfs_work(int u)
{
    check[u] = true;
    for(int v : g[u]){
        if(!check[v])
            dfs_work(v);
        d[u] += d[v];
    }
}

signed main()
{
//    freopen("oneway.inp" , "r" , stdin);
//    freopen("oneway.out" , "w" , stdout);

    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    cin >> n >> m;
    for(int i=1 ; i<=m ; ++i){
        int u, v;   cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
        canh[i] = {u, v};
    }

    for(int i=1 ; i<=n ; ++i){
        if(!num[i]){
            dfs(i, 0);
        }
    }

    for(int i=1 ; i<=m ; ++i){
        auto [u, v] = canh[i];
        int x = lab[u];
        int y = lab[v];
        if(x != y)
            g[max(x, y)].push_back(min(x, y));
    }

    cin >> q;
    for(int i=1 ; i<=q ; ++i){
        int u, v;   cin >> u >> v;
        u = lab[u]; v = lab[v];
        d[v]--; d[u]++;
    }

    for(int i=1 ; i<=scc ; ++i){
        if(!check[i]){
            dfs_work(i);
        }
    }

    for(int i=1 ; i<=m ; ++i){
        auto [u, v] = canh[i];
        int x = lab[u]; int y = lab[v];

        if(x == y){
            s[i] = 'B';
        }

        if(x > y)
        {
            if(d[y] > 0)    s[i] = 'L';
            if(d[y] < 0)    s[i] = 'R';
            if(d[y] == 0)   s[i] = 'B';
        }

        if(x < y)
        {
            if(d[x] > 0)    s[i] = 'R';
            if(d[x] < 0)    s[i] = 'L';
            if(d[x] == 0)   s[i] = 'B';
        }
    }

    for(int i=1 ; i<=m ; ++i){
        cout << s[i];
    }
}

/// code by yourlove ///

Compilation message

oneway.cpp: In function 'int main()':
oneway.cpp:90:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   90 |         auto [u, v] = canh[i];
      |              ^
oneway.cpp:111:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  111 |         auto [u, v] = canh[i];
      |              ^

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8540 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 8540 KB Output is correct
4 Correct 2 ms 8540 KB Output is correct
5 Correct 2 ms 8540 KB Output is correct
6 Correct 2 ms 8540 KB Output is correct
7 Correct 2 ms 8540 KB Output is correct
8 Correct 2 ms 8540 KB Output is correct
9 Correct 2 ms 8540 KB Output is correct
10 Correct 2 ms 8540 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8540 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 8540 KB Output is correct
4 Correct 2 ms 8540 KB Output is correct
5 Correct 2 ms 8540 KB Output is correct
6 Correct 2 ms 8540 KB Output is correct
7 Correct 2 ms 8540 KB Output is correct
8 Correct 2 ms 8540 KB Output is correct
9 Correct 2 ms 8540 KB Output is correct
10 Correct 2 ms 8540 KB Output is correct
11 Correct 25 ms 12892 KB Output is correct
12 Correct 26 ms 13916 KB Output is correct
13 Correct 30 ms 14940 KB Output is correct
14 Correct 36 ms 15956 KB Output is correct
15 Correct 33 ms 15952 KB Output is correct
16 Correct 36 ms 15588 KB Output is correct
17 Correct 36 ms 17564 KB Output is correct
18 Correct 43 ms 15776 KB Output is correct
19 Correct 36 ms 18516 KB Output is correct
20 Correct 27 ms 13648 KB Output is correct
21 Correct 26 ms 13104 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8540 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 8540 KB Output is correct
4 Correct 2 ms 8540 KB Output is correct
5 Correct 2 ms 8540 KB Output is correct
6 Correct 2 ms 8540 KB Output is correct
7 Correct 2 ms 8540 KB Output is correct
8 Correct 2 ms 8540 KB Output is correct
9 Correct 2 ms 8540 KB Output is correct
10 Correct 2 ms 8540 KB Output is correct
11 Correct 25 ms 12892 KB Output is correct
12 Correct 26 ms 13916 KB Output is correct
13 Correct 30 ms 14940 KB Output is correct
14 Correct 36 ms 15956 KB Output is correct
15 Correct 33 ms 15952 KB Output is correct
16 Correct 36 ms 15588 KB Output is correct
17 Correct 36 ms 17564 KB Output is correct
18 Correct 43 ms 15776 KB Output is correct
19 Correct 36 ms 18516 KB Output is correct
20 Correct 27 ms 13648 KB Output is correct
21 Correct 26 ms 13104 KB Output is correct
22 Correct 50 ms 17488 KB Output is correct
23 Correct 61 ms 15732 KB Output is correct
24 Correct 50 ms 15700 KB Output is correct
25 Correct 49 ms 20572 KB Output is correct
26 Correct 49 ms 17160 KB Output is correct
27 Correct 48 ms 15868 KB Output is correct
28 Correct 20 ms 10840 KB Output is correct
29 Correct 38 ms 13064 KB Output is correct
30 Correct 47 ms 13444 KB Output is correct
31 Correct 45 ms 13688 KB Output is correct
32 Correct 42 ms 16076 KB Output is correct