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Submission #1006356

# Submission time Handle Problem Language Result Execution time Memory
1006356 2024-06-23T20:28:44 Z serifefedartar One-Way Streets (CEOI17_oneway) C++17
100 / 100
 139 ms 36692 KB 
#include <bits/stdc++.h>
using namespace std;
 
#define fast ios::sync_with_stdio(0);cin.tie(0);
typedef long long ll;
#define f first
#define s second
#define LOGN 20
const ll MOD = 1e9 + 7;
const ll MAXN = 1e5 + 100;
 
vector<vector<int>> graph, G, G_rev;
vector<vector<pair<int,int>>> G2;
int mark[MAXN], a[MAXN], b[MAXN], vis[MAXN], par[MAXN], sz[MAXN], ways[MAXN];
int find(int node) {
    if (node == par[node])
        return node;
    return par[node] = find(par[node]);
}

void unite(int a, int b) {
    a = find(a);
    b = find(b);
    if (a == b)
        return ;
    if (sz[b] > sz[a])
        swap(a, b);
    par[b] = a;
    sz[a] += sz[b];
}

void dfs(int node, int parent) {
    vis[node] = 1;
    for (auto u : graph[node]) {
        if (u != parent && vis[u] != 2) {
            G[node].push_back(u);
            G_rev[u].push_back(node);
        }
        if (!vis[u])
            dfs(u, node);
    }
    vis[node] = 2;
}

stack<int> nds;
void dfs2(int node) {
    vis[node] = true;
    for (auto u : G[node]) {
        if (!vis[u])
            dfs2(u);
    }
    nds.push(node);
}

void dfs3(int node) {
    vis[node] = true;
    for (auto u : G_rev[node]) {
        if (vis[u])
            continue;
        unite(node, u);
        dfs3(u);
    }
}

void dfs4(int node) {
    vis[node] = true;
    for (auto u : G2[node]) {
        if (vis[u.f])
            continue;
        dfs4(u.f);
        mark[node] += mark[u.f];
        if (find(a[u.s]) == node) {
            if (mark[u.f] > 0)
                ways[u.s] = 1;
            else if (mark[u.f] < 0)
                ways[u.s] = 2;
        } else { // b[u.s] == node
            if (mark[u.f] > 0)
                ways[u.s] = 2;
            else if (mark[u.f] < 0)
                ways[u.s] = 1;
        }
    }
}

map<pair<int,int>,int> mp;
int main() {
    fast
    int n, m, q;
    cin >> n >> m;
 
    for (int i = 1; i <= n; i++)
        par[i] = i, sz[i] = 1;
    graph = vector<vector<int>>(n+1, vector<int>());
    G = vector<vector<int>>(n+1, vector<int>());
    G2 = vector<vector<pair<int,int>>>(n+1, vector<pair<int,int>>());
    G_rev = vector<vector<int>>(n+1, vector<int>());
    for (int i = 1; i <= m; i++) {
        cin >> a[i] >> b[i];
        mp[{min(a[i], b[i]), max(a[i], b[i])}]++;
        graph[a[i]].push_back(b[i]);
        graph[b[i]].push_back(a[i]);
    }
    for (int i = 1; i <= n; i++) {
        if (!vis[i])
            dfs(i, i);
    }
    for (int i = 1; i <= n; i++)
        vis[i] = 0;
    for (int i = 1; i <= n; i++) {
        if (!vis[i])
            dfs2(i);
    }
    for (int i = 1; i <= n; i++)
        vis[i] = 0;
    while (nds.size()) {
        int node = nds.top();
        nds.pop();
        if (!vis[node])
            dfs3(node);
    }
 
    for (int i = 1; i <= m; i++) {
        if (find(a[i]) == find(b[i]))
            ways[i] = -1;
        else {
            G2[find(a[i])].push_back({find(b[i]), i});
            G2[find(b[i])].push_back({find(a[i]), i});
        }
    }

    cin >> q;
    while (q--) {
        int a, b;
        cin >> a >> b;
        a = find(a);
        b = find(b);
        if (a == b)
            continue;

        mark[b] -= 1;
        mark[a] += 1;
    }

    for (int i = 1; i <= n; i++)
        vis[i] = false;
    for (int i = 1; i <= n; i++) {
        if (!vis[find(i)])
            dfs4(find(i));
    }

    for (int i = 1; i <= m; i++) {
        if (mp[{min(a[i], b[i]), max(a[i], b[i])}] > 1 || a[i] == b[i])
            cout << "B";
        else if (ways[i] == 1)
            cout << "L";
        else if (ways[i] == 2)
            cout << "R";
        else
            cout << "B";
    }
    cout << "\n";
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2396 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2648 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 0 ms 2652 KB Output is correct
7 Correct 1 ms 2652 KB Output is correct
8 Correct 1 ms 2652 KB Output is correct
9 Correct 1 ms 2652 KB Output is correct
10 Correct 1 ms 2652 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2396 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2648 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 0 ms 2652 KB Output is correct
7 Correct 1 ms 2652 KB Output is correct
8 Correct 1 ms 2652 KB Output is correct
9 Correct 1 ms 2652 KB Output is correct
10 Correct 1 ms 2652 KB Output is correct
11 Correct 86 ms 15444 KB Output is correct
12 Correct 93 ms 17744 KB Output is correct
13 Correct 88 ms 21460 KB Output is correct
14 Correct 103 ms 26748 KB Output is correct
15 Correct 123 ms 28112 KB Output is correct
16 Correct 120 ms 30544 KB Output is correct
17 Correct 95 ms 32848 KB Output is correct
18 Correct 112 ms 30656 KB Output is correct
19 Correct 114 ms 34124 KB Output is correct
20 Correct 84 ms 20308 KB Output is correct
21 Correct 78 ms 20052 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2396 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 1 ms 2652 KB Output is correct
4 Correct 1 ms 2648 KB Output is correct
5 Correct 1 ms 2652 KB Output is correct
6 Correct 0 ms 2652 KB Output is correct
7 Correct 1 ms 2652 KB Output is correct
8 Correct 1 ms 2652 KB Output is correct
9 Correct 1 ms 2652 KB Output is correct
10 Correct 1 ms 2652 KB Output is correct
11 Correct 86 ms 15444 KB Output is correct
12 Correct 93 ms 17744 KB Output is correct
13 Correct 88 ms 21460 KB Output is correct
14 Correct 103 ms 26748 KB Output is correct
15 Correct 123 ms 28112 KB Output is correct
16 Correct 120 ms 30544 KB Output is correct
17 Correct 95 ms 32848 KB Output is correct
18 Correct 112 ms 30656 KB Output is correct
19 Correct 114 ms 34124 KB Output is correct
20 Correct 84 ms 20308 KB Output is correct
21 Correct 78 ms 20052 KB Output is correct
22 Correct 112 ms 32848 KB Output is correct
23 Correct 139 ms 30800 KB Output is correct
24 Correct 111 ms 30500 KB Output is correct
25 Correct 121 ms 36692 KB Output is correct
26 Correct 110 ms 32340 KB Output is correct
27 Correct 130 ms 30988 KB Output is correct
28 Correct 35 ms 5208 KB Output is correct
29 Correct 101 ms 20156 KB Output is correct
30 Correct 86 ms 20236 KB Output is correct
31 Correct 93 ms 20340 KB Output is correct
32 Correct 93 ms 24404 KB Output is correct