oj.uz

Submission #866771

# Submission time Handle Problem Language Result Execution time Memory
866771 2023-10-27T03:21:26 Z _anhxinloi_ One-Way Streets (CEOI17_oneway) C++14
100 / 100
 53 ms 20560 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;
            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:84:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   84 |         auto [u, v] = canh[i];
      |              ^
oneway.cpp:105:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  105 |         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 2 ms 8540 KB Output is correct
3 Correct 2 ms 8536 KB Output is correct
4 Correct 2 ms 8792 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 8640 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 2 ms 8540 KB Output is correct
3 Correct 2 ms 8536 KB Output is correct
4 Correct 2 ms 8792 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 8640 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 30 ms 12880 KB Output is correct
12 Correct 26 ms 13916 KB Output is correct
13 Correct 31 ms 15072 KB Output is correct
14 Correct 33 ms 15952 KB Output is correct
15 Correct 33 ms 15956 KB Output is correct
16 Correct 37 ms 15696 KB Output is correct
17 Correct 36 ms 17440 KB Output is correct
18 Correct 36 ms 15696 KB Output is correct
19 Correct 36 ms 18524 KB Output is correct
20 Correct 29 ms 13664 KB Output is correct
21 Correct 26 ms 13128 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 2 ms 8540 KB Output is correct
3 Correct 2 ms 8536 KB Output is correct
4 Correct 2 ms 8792 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 8640 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 30 ms 12880 KB Output is correct
12 Correct 26 ms 13916 KB Output is correct
13 Correct 31 ms 15072 KB Output is correct
14 Correct 33 ms 15952 KB Output is correct
15 Correct 33 ms 15956 KB Output is correct
16 Correct 37 ms 15696 KB Output is correct
17 Correct 36 ms 17440 KB Output is correct
18 Correct 36 ms 15696 KB Output is correct
19 Correct 36 ms 18524 KB Output is correct
20 Correct 29 ms 13664 KB Output is correct
21 Correct 26 ms 13128 KB Output is correct
22 Correct 50 ms 17384 KB Output is correct
23 Correct 50 ms 15708 KB Output is correct
24 Correct 51 ms 15540 KB Output is correct
25 Correct 49 ms 20560 KB Output is correct
26 Correct 47 ms 16988 KB Output is correct
27 Correct 51 ms 15816 KB Output is correct
28 Correct 20 ms 10960 KB Output is correct
29 Correct 39 ms 13144 KB Output is correct
30 Correct 41 ms 13144 KB Output is correct
31 Correct 40 ms 13912 KB Output is correct
32 Correct 53 ms 16212 KB Output is correct