oj.uz

Submission #161692

# Submission time Handle Problem Language Result Execution time Memory
161692 2019-11-03T18:30:44 Z Minnakhmetov One-Way Streets (CEOI17_oneway) C++14
100 / 100
 239 ms 34552 KB 
#include <bits/stdc++.h>
    
#define ll long long
#define all(aaa) aaa.begin(), aaa.end()
 
using namespace std;

struct E {
    int to, i;
    bool straight;
};

const int N = 1e5 + 5, L = 19;
vector<E> g[N], g2[N], t[N];
int tin[N], mnt[N], tint[N], toutt[N], w[N][2], par[N][L],
    col[N];
int timer = 1;
string ans;

bool used[N];

void dfs(int node, int anc) {
    mnt[node] = tin[node] = timer++;

    for (E e : g[node]) {
        if (e.i != anc) {
            if (!tin[e.to]) {
                dfs(e.to, e.i);
                mnt[node] = min(mnt[node], mnt[e.to]);
            }
            else {
                mnt[node] = min(mnt[node], tin[e.to]);
            }

            if (mnt[e.to] <= tin[node]) {
                g2[node].push_back(e);
                g2[e.to].push_back({node, e.i, e.straight ^ 1});
            }
        }
    }
}

void dive(int node, int c) {
    col[node] = c;

    for (E e : g2[node]) {
        if (col[e.to] == -1) {
            dive(e.to, c);
        }
    }

    for (E e : g[node]) {
        if (col[e.to] != -1 && col[e.to] != col[node]) {
            t[col[node]].push_back({col[e.to], e.i, e.straight});
            t[col[e.to]].push_back({col[node], e.i, e.straight ^ 1});
        }
    }
}

void walk(int node) {
    tint[node] = ++timer;
    for (int i = 1; i < L; i++) {
        par[node][i] = par[par[node][i - 1]][i - 1];
    }

    for (E e : t[node]) {
        if (e.to != par[node][0]) {
            par[e.to][0] = node;
            walk(e.to);
        }
    }

    toutt[node] = timer;
}

bool upper(int a, int b) {
    return tint[a] <= tint[b] && toutt[a] >= toutt[b];
}

int getLca(int a, int b) {
    if (upper(a, b))
        return a;
    for (int i = L - 1; i >= 0; i--) {
        if (!upper(par[a][i], b))
            a = par[a][i];
    }
    return par[a][0];
}

void roam(int node) {
    used[node] = 1;

    for (E e : t[node]) {
        if (e.to != par[node][0]) {
            roam(e.to);
            if (w[e.to][0]) {
                ans[e.i] = (e.straight ? 'L' : 'R');
            }
            else if (w[e.to][1]) {
                ans[e.i] = (e.straight ? 'R' : 'L');
            }
            w[node][0] += w[e.to][0];
            w[node][1] += w[e.to][1];
        }
    }
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);

    int n, m, p;
    cin >> n >> m;

    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        a--, b--;
        g[a].push_back({b, i, true});
        g[b].push_back({a, i, false});
    }

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

    fill(col, col + n, -1);
    int cc = 0;

    for (int i = 0; i < n; i++) {
        if (col[i] == -1) {
            dive(i, cc++);
        }
    }

    // for (int i = 0; i < cc; i++) {
    //     for (E e : t[i]) {
    //         cout << i + 1 << " " << e.to + 1 << "\n";
    //     }
    // }

    for (int i = 0; i < cc; i++) {
        if (!tint[i]) {
            fill(par[i], par[i] + L, i);
            walk(i);
        }
    }

    ans.resize(m, 'B');

    cin >> p;

    for (int i = 0; i < p; i++) {
        int a, b;
        cin >> a >> b;
        a--, b--;

        a = col[a];
        b = col[b];

        int lca = getLca(a, b);

        w[a][0]++;
        w[lca][0]--;
        w[b][1]++;
        w[lca][1]--;
    }

    for (int i = 0; i < cc; i++) {
        if (!used[i])
            roam(i);
    }

    cout << ans;

    return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 7420 KB Output is correct
2 Correct 8 ms 7416 KB Output is correct
3 Correct 9 ms 7544 KB Output is correct
4 Correct 9 ms 7672 KB Output is correct
5 Correct 9 ms 7672 KB Output is correct
6 Correct 9 ms 7544 KB Output is correct
7 Correct 10 ms 7672 KB Output is correct
8 Correct 10 ms 7672 KB Output is correct
9 Correct 9 ms 7544 KB Output is correct
10 Correct 9 ms 7548 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 7420 KB Output is correct
2 Correct 8 ms 7416 KB Output is correct
3 Correct 9 ms 7544 KB Output is correct
4 Correct 9 ms 7672 KB Output is correct
5 Correct 9 ms 7672 KB Output is correct
6 Correct 9 ms 7544 KB Output is correct
7 Correct 10 ms 7672 KB Output is correct
8 Correct 10 ms 7672 KB Output is correct
9 Correct 9 ms 7544 KB Output is correct
10 Correct 9 ms 7548 KB Output is correct
11 Correct 93 ms 21112 KB Output is correct
12 Correct 109 ms 22008 KB Output is correct
13 Correct 124 ms 22520 KB Output is correct
14 Correct 121 ms 24056 KB Output is correct
15 Correct 151 ms 24860 KB Output is correct
16 Correct 155 ms 27512 KB Output is correct
17 Correct 159 ms 29372 KB Output is correct
18 Correct 154 ms 27452 KB Output is correct
19 Correct 173 ms 31004 KB Output is correct
20 Correct 111 ms 20344 KB Output is correct
21 Correct 99 ms 19884 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 7420 KB Output is correct
2 Correct 8 ms 7416 KB Output is correct
3 Correct 9 ms 7544 KB Output is correct
4 Correct 9 ms 7672 KB Output is correct
5 Correct 9 ms 7672 KB Output is correct
6 Correct 9 ms 7544 KB Output is correct
7 Correct 10 ms 7672 KB Output is correct
8 Correct 10 ms 7672 KB Output is correct
9 Correct 9 ms 7544 KB Output is correct
10 Correct 9 ms 7548 KB Output is correct
11 Correct 93 ms 21112 KB Output is correct
12 Correct 109 ms 22008 KB Output is correct
13 Correct 124 ms 22520 KB Output is correct
14 Correct 121 ms 24056 KB Output is correct
15 Correct 151 ms 24860 KB Output is correct
16 Correct 155 ms 27512 KB Output is correct
17 Correct 159 ms 29372 KB Output is correct
18 Correct 154 ms 27452 KB Output is correct
19 Correct 173 ms 31004 KB Output is correct
20 Correct 111 ms 20344 KB Output is correct
21 Correct 99 ms 19884 KB Output is correct
22 Correct 239 ms 30496 KB Output is correct
23 Correct 211 ms 28372 KB Output is correct
24 Correct 213 ms 28664 KB Output is correct
25 Correct 217 ms 34552 KB Output is correct
26 Correct 231 ms 30028 KB Output is correct
27 Correct 215 ms 28408 KB Output is correct
28 Correct 56 ms 17528 KB Output is correct
29 Correct 150 ms 20984 KB Output is correct
30 Correct 127 ms 20984 KB Output is correct
31 Correct 132 ms 21608 KB Output is correct
32 Correct 152 ms 25948 KB Output is correct