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Submission #1003760

# Submission time Handle Problem Language Result Execution time Memory
1003760 2024-06-20T16:52:47 Z coolboy19521 One-Way Streets (CEOI17_oneway) C++17
100 / 100
 162 ms 61188 KB 
#pragma GCC optimize("Ofast")
#include "bits/stdc++.h"
#define int long long

using namespace std;

const int sz = 2e5 + 10;
const int sm = 25;

vector<pair<int, int>> aj[sz], ajgr[sz];
int br[sz], gr[sz], dp[sz];
int in[sz], lo[sz];
int pn[sz], pe[sz];
int le[sz], ri[sz];
int up[sm][sz];
int n, m, p;
bool dr[sz];
char la[sz];
int tr;

void taj(int v, int p = 0) {
    in[v] = lo[v] = ++tr;
    bool ps = false;
    for (auto& u : aj[v]) {
        int to = u.first, nm = u.second;
        if (to == p && !ps) {
            ps = true;
            continue;
        } else if (in[to]) {
            lo[v] = min(lo[v], in[to]);
        } else {
            taj(to, v);
            lo[v] = min(lo[v], lo[to]);
            if (lo[to] > in[v]) {
                br[nm] = true;
            }
        }
    }
}

void cmp(int v, int gn) {
    gr[v] = gn;
    for (auto& u : aj[v]) {
        int to = u.first, nm = u.second;
        if (!gr[to] && !br[nm]) {
            cmp(to, gn);
        }
    }
}

void dpt(int v, int p = 0, int d = 1) {
    up[0][v] = pn[v];
    dp[v] = d;
    for (auto& u : ajgr[v]) {
        int to = u.first, nm = u.second;
        if (to != p) {
            pn[to] = v;
            pe[to] = nm;
            dpt(to, v, d + 1);
        }
    }
}

int lca(int a, int b) {
    if (dp[a] > dp[b]) {
        swap(a, b);
    }
    int d = dp[b] - dp[a];
    for (int i = 0; i < sm; i++) {
        if (d & (1ll << i)) {
            b = up[i][b];
        }
    }
    if (a == b) {
        return a;
    }
    for (int i = sm - 1; i >= 0; i--) {
        if (up[i][a] != up[i][b]) {
            a = up[i][a];
            b = up[i][b];
        }
    }
    return up[0][a];
}

void gdr(int a, int b, int d) {
    if (a == b) {
        return;
    }
    if (!dr[a]) {
        dr[a] = true;
        int to = pn[a];
        int nm = pe[a];
        int gna = gr[le[nm]];
        if (0 == d) {
            if (gna == a) {
                la[nm] = 'R';
            } else {
                la[nm] = 'L';
            }
        } else {
            if (gna == a) {
                la[nm] = 'L';
            } else {
                la[nm] = 'R';
            }
        }
        gdr(to, b, d);
    }
}

signed main() {
    cin.tie(nullptr)->sync_with_stdio(false);

    cin >> n >> m;

    for (int i = 1; i <= m; i++) {
        int a, b;
        cin >> a >> b;

        aj[a].emplace_back(b, i);
        aj[b].emplace_back(a, i);
        le[i] = a;
        ri[i] = b;
        la[i] = 'B';
    }

    for (int i = 1; i <= n; i++) {
        if (!in[i]) {
            taj(i);
        }
    }

    int gn = 0;

    for (int i = 1; i <= n; i++) {
        if (!gr[i]) {
            cmp(i, ++gn);
        }
    }

    for (int i = 1; i <= m; i++) {
        if (br[i]) {
            int gna = gr[le[i]];
            int gnb = gr[ri[i]];
            ajgr[gna].emplace_back(gnb, i);
            ajgr[gnb].emplace_back(gna, i);
        }
    }

    for (int i = 1; i <= gn; i++) {
        if (!dp[i]) {
            dpt(i);
        }
    }

    for (int i = 1; i < sm; i++) {
        for (int j = 1; j <= gn; j++) {
            up[i][j] = up[i - 1][up[i - 1][j]];
        }
    }

    vector<vector<int>> ord;

    int q;
    cin >> q;

    while (q--) {
        int a, b;
        cin >> a >> b;

        a = gr[a];
        b = gr[b];
        int l = lca(a, b);
        ord.push_back({dp[l], a, b, l});
    }

    sort(begin(ord), end(ord));

    for (auto& i : ord) {
        int a = i[1];
        int b = i[2];
        int l = i[3];
        gdr(a, l, 0);
        gdr(b, l, 1);
    }

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

    cout << '\n';
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 10052 KB Output is correct
2 Correct 4 ms 10076 KB Output is correct
3 Correct 4 ms 10076 KB Output is correct
4 Correct 5 ms 10332 KB Output is correct
5 Correct 5 ms 10332 KB Output is correct
6 Correct 5 ms 10000 KB Output is correct
7 Correct 5 ms 10376 KB Output is correct
8 Correct 5 ms 10488 KB Output is correct
9 Correct 5 ms 10076 KB Output is correct
10 Correct 5 ms 10076 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 10052 KB Output is correct
2 Correct 4 ms 10076 KB Output is correct
3 Correct 4 ms 10076 KB Output is correct
4 Correct 5 ms 10332 KB Output is correct
5 Correct 5 ms 10332 KB Output is correct
6 Correct 5 ms 10000 KB Output is correct
7 Correct 5 ms 10376 KB Output is correct
8 Correct 5 ms 10488 KB Output is correct
9 Correct 5 ms 10076 KB Output is correct
10 Correct 5 ms 10076 KB Output is correct
11 Correct 32 ms 19540 KB Output is correct
12 Correct 33 ms 21332 KB Output is correct
13 Correct 38 ms 23644 KB Output is correct
14 Correct 48 ms 29900 KB Output is correct
15 Correct 54 ms 33024 KB Output is correct
16 Correct 65 ms 48208 KB Output is correct
17 Correct 64 ms 49720 KB Output is correct
18 Correct 64 ms 48200 KB Output is correct
19 Correct 62 ms 51028 KB Output is correct
20 Correct 33 ms 20052 KB Output is correct
21 Correct 30 ms 20828 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 10052 KB Output is correct
2 Correct 4 ms 10076 KB Output is correct
3 Correct 4 ms 10076 KB Output is correct
4 Correct 5 ms 10332 KB Output is correct
5 Correct 5 ms 10332 KB Output is correct
6 Correct 5 ms 10000 KB Output is correct
7 Correct 5 ms 10376 KB Output is correct
8 Correct 5 ms 10488 KB Output is correct
9 Correct 5 ms 10076 KB Output is correct
10 Correct 5 ms 10076 KB Output is correct
11 Correct 32 ms 19540 KB Output is correct
12 Correct 33 ms 21332 KB Output is correct
13 Correct 38 ms 23644 KB Output is correct
14 Correct 48 ms 29900 KB Output is correct
15 Correct 54 ms 33024 KB Output is correct
16 Correct 65 ms 48208 KB Output is correct
17 Correct 64 ms 49720 KB Output is correct
18 Correct 64 ms 48200 KB Output is correct
19 Correct 62 ms 51028 KB Output is correct
20 Correct 33 ms 20052 KB Output is correct
21 Correct 30 ms 20828 KB Output is correct
22 Correct 162 ms 57852 KB Output is correct
23 Correct 141 ms 56572 KB Output is correct
24 Correct 130 ms 56532 KB Output is correct
25 Correct 137 ms 61188 KB Output is correct
26 Correct 142 ms 57660 KB Output is correct
27 Correct 140 ms 56572 KB Output is correct
28 Correct 33 ms 23304 KB Output is correct
29 Correct 57 ms 27908 KB Output is correct
30 Correct 59 ms 28164 KB Output is correct
31 Correct 55 ms 28160 KB Output is correct
32 Correct 82 ms 38792 KB Output is correct