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Submission #518207

# Submission time Handle Problem Language Result Execution time Memory
518207 2022-01-23T08:56:58 Z blue One-Way Streets (CEOI17_oneway) C++17
100 / 100
 234 ms 35912 KB 
#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;

using vi = vector<int>;
using vvi = vector<vi>;
using pii = pair<int, int>;

const int mx = 100'000;


int n, m;

vi edge[1+mx];

vi nw_edge[1+mx];
vi nw_rev[1+mx];

vi visit(1+mx, 0);

vi ee;

void dfs(int u, int p)
{
    visit[u] = 1;
    for(int v: edge[u])
    {
        if(v == p) continue;

        if(visit[v])
        {
            // cerr << v << " ->* " << u << '\n';
            nw_edge[v].push_back(u);
            nw_rev[u].push_back(v);
        }
        else
        {
            // cerr << u << " -> " << v << '\n';
            nw_edge[u].push_back(v);
            nw_rev[v].push_back(u);
            dfs(v, u);
        }
    }

    ee.push_back(u);
}


vi bcc(1+mx, 0);
int ct = 0;
vi bcc_list[1+mx];

void dfs2(int u)
{
    bcc[u] = ct;
    bcc_list[ct].push_back(u);
    for(int v: nw_rev[u])
    {
        if(bcc[v]) continue;
        dfs2(v);
    }
}


int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> m;

    vi a(1+m), b(1+m);

    for(int e = 1; e <= m; e++)
    {
        cin >> a[e] >> b[e];
        edge[a[e]].push_back(b[e]);
        edge[b[e]].push_back(a[e]);
    }


    for(int u = 1; u <= n; u++)
    {
        if(visit[u]) continue;
        dfs(u, 0);
    }

    // for(int u = 1; u <= n; u++)
    // {
    //     cerr << u << " : ";
    //     for(int v: nw_edge[u]) cerr << v << ' ';
    //     cerr << '\n';
    // }

    reverse(ee.begin(), ee.end());

    for(int u: ee)
    {
        if(bcc[u]) continue;
        ++ct;
        dfs2(u);
    }


    // for(int i = 1; i <= ct; i++)
    // {
    //     for(int u: bcc_list[i]) cerr << u << ' ';
    //     cerr << '\n';
    // }

    vector<pii> bcc_edge[1+ct];
    vi deg(1+ct, 0);

    vector<char> ans(1+m, 'B');

    for(int e = 1; e <= m; e++)
    {
        if(bcc[a[e]] == bcc[b[e]])
        {
            continue;
        }

        bcc_edge[ bcc[a[e]] ].push_back({bcc[b[e]], +e});
        bcc_edge[ bcc[b[e]] ].push_back({bcc[a[e]], -e});
        deg[bcc[a[e]]]++;
        deg[bcc[b[e]]]++;
    }







    vi score(1+ct, 0);

    int p;
    cin >> p;

    for(int z = 1; z <= p; z++)
    {
        int x, y;
        cin >> x >> y;

        score[bcc[x]]++;
        score[bcc[y]]--;
    }

    fill(visit.begin(), visit.end(), 0);

    queue<int> tbv;

    for(int u = 1; u <= ct; u++)
    {
        if(deg[u] == 1)
        {
            tbv.push(u);
        }
    }

    while(!tbv.empty())
    {
        int u = tbv.front();
        tbv.pop();

        deg[u] = -5;

        // cerr << "u = " << u << " : ";
        // for(int w: bcc_list[u]) cerr << w << ' ';
        // cerr << '\n';

        for(pii e: bcc_edge[u])
        {
            int v = e.first;
            int id = e.second;

            if(deg[v] < 0) continue;

            deg[v]--;

            // cerr << "par " << u << " = " << v << '\n';
            // cerr << score[u] << '\n';

            if(score[u] > 0)
            {
                // cerr << "#\n";
                if(id > 0)
                    ans[id] = 'R';
                else
                    ans[-id] = 'L';
            }
            else if(score[u] < 0)
            {
                // cerr << "? " << id << '\n';
                if(id > 0)
                    ans[id] = 'L';
                else
                    ans[-id] = 'R';
            }

            score[v] += score[u];
            score[u] = 0;

            if(deg[v] == 1) tbv.push(v);
        }
    }

    for(int e = 1; e <= m; e++) cout << ans[e];
    cout << '\n';
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 10644 KB Output is correct
2 Correct 6 ms 10448 KB Output is correct
3 Correct 7 ms 10536 KB Output is correct
4 Correct 10 ms 10724 KB Output is correct
5 Correct 10 ms 10644 KB Output is correct
6 Correct 9 ms 10596 KB Output is correct
7 Correct 8 ms 10648 KB Output is correct
8 Correct 9 ms 10704 KB Output is correct
9 Correct 10 ms 10576 KB Output is correct
10 Correct 9 ms 10476 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 10644 KB Output is correct
2 Correct 6 ms 10448 KB Output is correct
3 Correct 7 ms 10536 KB Output is correct
4 Correct 10 ms 10724 KB Output is correct
5 Correct 10 ms 10644 KB Output is correct
6 Correct 9 ms 10596 KB Output is correct
7 Correct 8 ms 10648 KB Output is correct
8 Correct 9 ms 10704 KB Output is correct
9 Correct 10 ms 10576 KB Output is correct
10 Correct 9 ms 10476 KB Output is correct
11 Correct 79 ms 18284 KB Output is correct
12 Correct 121 ms 19696 KB Output is correct
13 Correct 157 ms 21232 KB Output is correct
14 Correct 152 ms 24572 KB Output is correct
15 Correct 175 ms 25536 KB Output is correct
16 Correct 209 ms 31196 KB Output is correct
17 Correct 128 ms 31276 KB Output is correct
18 Correct 197 ms 31140 KB Output is correct
19 Correct 149 ms 32356 KB Output is correct
20 Correct 120 ms 20004 KB Output is correct
21 Correct 105 ms 19660 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 10644 KB Output is correct
2 Correct 6 ms 10448 KB Output is correct
3 Correct 7 ms 10536 KB Output is correct
4 Correct 10 ms 10724 KB Output is correct
5 Correct 10 ms 10644 KB Output is correct
6 Correct 9 ms 10596 KB Output is correct
7 Correct 8 ms 10648 KB Output is correct
8 Correct 9 ms 10704 KB Output is correct
9 Correct 10 ms 10576 KB Output is correct
10 Correct 9 ms 10476 KB Output is correct
11 Correct 79 ms 18284 KB Output is correct
12 Correct 121 ms 19696 KB Output is correct
13 Correct 157 ms 21232 KB Output is correct
14 Correct 152 ms 24572 KB Output is correct
15 Correct 175 ms 25536 KB Output is correct
16 Correct 209 ms 31196 KB Output is correct
17 Correct 128 ms 31276 KB Output is correct
18 Correct 197 ms 31140 KB Output is correct
19 Correct 149 ms 32356 KB Output is correct
20 Correct 120 ms 20004 KB Output is correct
21 Correct 105 ms 19660 KB Output is correct
22 Correct 195 ms 32408 KB Output is correct
23 Correct 234 ms 32468 KB Output is correct
24 Correct 222 ms 32308 KB Output is correct
25 Correct 229 ms 35912 KB Output is correct
26 Correct 173 ms 32480 KB Output is correct
27 Correct 194 ms 32468 KB Output is correct
28 Correct 49 ms 15316 KB Output is correct
29 Correct 106 ms 20640 KB Output is correct
30 Correct 119 ms 20796 KB Output is correct
31 Correct 154 ms 21224 KB Output is correct
32 Correct 127 ms 25824 KB Output is correct