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Submission #571271

# Submission time Handle Problem Language Result Execution time Memory
571271 2022-06-01T15:52:10 Z piOOE One-Way Streets (CEOI17_oneway) C++17
100 / 100
 183 ms 32116 KB 
#include <bits/stdc++.h>

using namespace std;

#define sz(x) ((int)size(x))
#define all(x) begin(x), end(x)
#define trace(x) cout << #x << ": " << (x) << endl;

typedef long long ll;

mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

int rand(int l, int r) { return (int) ((ll) rnd() % (r - l + 1)) + l; }

template<typename T>
bool ckmn(T &x, T y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}

template<typename T>
bool ckmx(T &x, T y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}

const int N = 100001, infI = 1e9 + 7;
const ll infL = 3e18;

int n, m, k;
int A[N], B[N], X[N], Y[N], tin[N], fup[N], T = 0, color[N], parent[N], idx_par[N], lca[N];
bool bridge[N], used[N];

vector<pair<int, int>> g[N], new_g[N], qu[N];
int p[N], sz[N], pp[N], ssz[N], leader[N];

int get(int a) {
    return a == p[a] ? a : p[a] = get(p[a]);
}

int gget(int a) {
    return a == pp[a] ? a : pp[a] = gget(pp[a]);
}

int mrg(int a, int b) {
    a = get(a);
    b = get(b);
    if (a == b) {
        return 0;
    }
    sz[a] += sz[b];
    p[b] = a;
    return true;
}

int mmrg(int a, int b) {
    a = gget(a);
    b = gget(b);
    assert(a != b);
    if (ssz[a] < ssz[b]) {
        swap(a, b);
    }
    ssz[a] += ssz[b];
    pp[b] = a;
    return a;
}

void dfs(int v, int j) {
    tin[v] = fup[v] = T++;
    used[v] = true;
    for (auto [to, i]: g[v]) {
        if (i != j) {
            if (used[to]) {
                ckmn(fup[v], tin[to]);
            } else {
                dfs(to, i);
                ckmn(fup[v], fup[to]);
                if (fup[to] > tin[v]) {
                    bridge[i] = true;
                }
            }
        }
    }
}

string ans;

void paint(int v) {
    used[v] = true;
    color[v] = T;
    for (auto [to, i]: g[v]) {
        if (!bridge[i] && !used[to]) {
            paint(to);
        }
    }
}

void zhfs(int v) {
    used[v] = true;
    leader[v] = v;
    for (auto [to, i]: new_g[v]) {
        if (to != parent[v]) {
            parent[to] = v;
            idx_par[to] = i;
            zhfs(to);
            leader[mmrg(v, to)] = v;
        }
    }
    for (auto[to, i] : qu[v]) {
        if (used[to]) {
            lca[i] = leader[gget(to)];
        }
    }
}

void union_path(int a, int c, int tp) {
    a = get(a);
    while (a != get(c)) {
        mrg(parent[a], a);
        if (color[A[idx_par[a]]] == a) {
            if (tp == 0) {
                ans[idx_par[a]] = 'R';
            } else {
                ans[idx_par[a]] = 'L';
            }
        } else {
            if (tp == 1) {
                ans[idx_par[a]] = 'R';
            } else {
                ans[idx_par[a]] = 'L';
            }
        }
        a = get(a);
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> n >> m;
    for (int i = 0; i < m; ++i) {
        cin >> A[i] >> B[i];
        --A[i], --B[i];
        g[A[i]].emplace_back(B[i], i);
        g[B[i]].emplace_back(A[i], i);
    }
    cin >> k;
    for (int i = 0; i < k; ++i) {
        cin >> X[i] >> Y[i];
        --X[i], --Y[i];
    }
    iota(leader, leader + n, 0);
    for (int i = 0; i < n; ++i) {
        if (!used[i]) {
            dfs(i, -1);
        }
    }
    memset(used, 0, sizeof(used));
    memset(idx_par, -1, sizeof(idx_par));
    T = 0;
    for (int i = 0; i < n; ++i) {
        if (!used[i]) {
            paint(i);
            ++T;
        }
    }
    for (int i = 0; i < m; ++i) {
        if (bridge[i]) {
            new_g[color[A[i]]].emplace_back(color[B[i]], i);
            new_g[color[B[i]]].emplace_back(color[A[i]], i);
        }
    }
    for (int i = 0; i < k; ++i) {
        qu[color[X[i]]].emplace_back(color[Y[i]], i);
        qu[color[Y[i]]].emplace_back(color[X[i]], i);
    }
    memset(used, 0, sizeof(used));
    fill(sz, sz + T, 1);
    fill(ssz, ssz + T, 1);
    iota(pp, pp + T, 0);
    iota(p, p + T, 0);
    for (int i = 0; i < T; ++i) {
        if (!used[i]) {
            zhfs(i);
        }
    }
    ans = string(m, 'B');
    for (int i = 0; i < k; ++i) {
        int a = color[X[i]];
        int b = color[Y[i]];
        int c = lca[i];
        union_path(a, c, 0);
        union_path(b, c, 1);
    }
    cout << ans;
    return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 7892 KB Output is correct
2 Correct 5 ms 7888 KB Output is correct
3 Correct 5 ms 7892 KB Output is correct
4 Correct 5 ms 8028 KB Output is correct
5 Correct 5 ms 8040 KB Output is correct
6 Correct 5 ms 7892 KB Output is correct
7 Correct 5 ms 8032 KB Output is correct
8 Correct 6 ms 8020 KB Output is correct
9 Correct 5 ms 7892 KB Output is correct
10 Correct 5 ms 7892 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 7892 KB Output is correct
2 Correct 5 ms 7888 KB Output is correct
3 Correct 5 ms 7892 KB Output is correct
4 Correct 5 ms 8028 KB Output is correct
5 Correct 5 ms 8040 KB Output is correct
6 Correct 5 ms 7892 KB Output is correct
7 Correct 5 ms 8032 KB Output is correct
8 Correct 6 ms 8020 KB Output is correct
9 Correct 5 ms 7892 KB Output is correct
10 Correct 5 ms 7892 KB Output is correct
11 Correct 47 ms 13900 KB Output is correct
12 Correct 52 ms 14784 KB Output is correct
13 Correct 70 ms 15976 KB Output is correct
14 Correct 85 ms 17752 KB Output is correct
15 Correct 87 ms 18436 KB Output is correct
16 Correct 82 ms 21076 KB Output is correct
17 Correct 90 ms 22688 KB Output is correct
18 Correct 110 ms 21028 KB Output is correct
19 Correct 84 ms 24064 KB Output is correct
20 Correct 46 ms 14508 KB Output is correct
21 Correct 40 ms 14488 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 7892 KB Output is correct
2 Correct 5 ms 7888 KB Output is correct
3 Correct 5 ms 7892 KB Output is correct
4 Correct 5 ms 8028 KB Output is correct
5 Correct 5 ms 8040 KB Output is correct
6 Correct 5 ms 7892 KB Output is correct
7 Correct 5 ms 8032 KB Output is correct
8 Correct 6 ms 8020 KB Output is correct
9 Correct 5 ms 7892 KB Output is correct
10 Correct 5 ms 7892 KB Output is correct
11 Correct 47 ms 13900 KB Output is correct
12 Correct 52 ms 14784 KB Output is correct
13 Correct 70 ms 15976 KB Output is correct
14 Correct 85 ms 17752 KB Output is correct
15 Correct 87 ms 18436 KB Output is correct
16 Correct 82 ms 21076 KB Output is correct
17 Correct 90 ms 22688 KB Output is correct
18 Correct 110 ms 21028 KB Output is correct
19 Correct 84 ms 24064 KB Output is correct
20 Correct 46 ms 14508 KB Output is correct
21 Correct 40 ms 14488 KB Output is correct
22 Correct 160 ms 28548 KB Output is correct
23 Correct 158 ms 26708 KB Output is correct
24 Correct 141 ms 26828 KB Output is correct
25 Correct 149 ms 32116 KB Output is correct
26 Correct 149 ms 28148 KB Output is correct
27 Correct 183 ms 26708 KB Output is correct
28 Correct 38 ms 14876 KB Output is correct
29 Correct 64 ms 18344 KB Output is correct
30 Correct 63 ms 18892 KB Output is correct
31 Correct 73 ms 19164 KB Output is correct
32 Correct 86 ms 22964 KB Output is correct