oj.uz

Submission #822936

# Submission time Handle Problem Language Result Execution time Memory
822936 2023-08-12T05:26:03 Z arush_agu One-Way Streets (CEOI17_oneway) C++17
100 / 100
 145 ms 64580 KB 
#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#ifdef DEBUG
#include <time.h>
#endif

#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x)                                                                 \
  {                                                                            \
    ++recur_depth;                                                             \
    auto x_ = x;                                                               \
    --recur_depth;                                                             \
    cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":"           \
         << __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl;         \
  }
#else
#define dbg(x)
#endif

using namespace std;
using namespace __gnu_pbds;

typedef pair<int, int> ii;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;

typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;

typedef vector<bool> vb;

template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
                         tree_order_statistics_node_update>;

template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
  return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
                                    !is_same<T_container, string>::value,
                                    typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
  os << '{';
  string sep;
  for (const T &x : v)
    os << sep << x, sep = ", ";
  return os << '}';
}

const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e9;
const ld EPS = 1e-9;

struct Edge {
  int u, v, idx, res = 2;
  bool is_bridge;
};

struct ST {
  const int MAXLG = 22;

  int n;
  vi lg2;
  vvii st;

  ST(int n, vii &a) : n(n) {
    st = vvii(MAXLG, vii(n));
    st[0] = a;

    for (int j = 1; j < MAXLG; j++)
      for (int i = 0; i + (1 << j) <= n; i++)
        st[j][i] = min(st[j - 1][i], st[j - 1][i + (1 << (j - 1))]);

    lg2 = vi(n + 2);
    lg2[1] = 0;
    for (int i = 2; i <= n; i++)
      lg2[i] = lg2[i / 2] + 1;
  }

  int query(int l, int r) {
    if (l > r)
      swap(l, r);
    int k = lg2[r - l + 1];
    return min(st[k][l], st[k][r - (1 << k) + 1]).second;
  }
};

void solve() {
  int n, m;
  cin >> n >> m;
  vector<Edge> eds(m);
  vvii adj(n);
  for (int i = 0; i < m; i++) {
    Edge &e = eds[i];
    cin >> e.u >> e.v;
    e.u--, e.v--;
    e.idx = i;

    adj[e.u].push_back({e.v, i});
    adj[e.v].push_back({e.u, i});
  }

  int p;
  cin >> p;
  vi st(p), en(p);
  for (int i = 0; i < p; i++)
    cin >> st[i] >> en[i], st[i]--, en[i]--;

  int timer = 0;
  vi tin(n), low(n);
  vb vis(n);
  function<void(int, int)> f = [&](int u, int p_e_id) {
    vis[u] = 1;
    tin[u] = low[u] = timer++;

    for (auto [v, i] : adj[u])
      if (i != p_e_id) {
        if (vis[v])
          low[u] = min(low[u], low[v]);
        else {
          f(v, i);
          low[u] = min(low[u], low[v]);
          if (low[v] > tin[u])
            eds[i].is_bridge = 1;
        }
      }
  };
  for (int i = 0; i < n; i++)
    if (!vis[i])
      f(i, -1);

  vis = vb(n);
  vi cc_id(n);
  function<void(int, int)> g = [&](int u, int c_id) {
    vis[u] = 1;
    cc_id[u] = c_id;
    for (auto [v, i] : adj[u])
      if (!vis[v] && !eds[i].is_bridge)
        g(v, c_id);
  };
  int cidx = 0;
  for (int i = 0; i < n; i++)
    if (!vis[i])
      g(i, cidx++);

  vvii tree(cidx);
  for (Edge e : eds)
    if (cc_id[e.u] != cc_id[e.v]) {
      tree[cc_id[e.u]].push_back({cc_id[e.v], e.idx});
      tree[cc_id[e.v]].push_back({cc_id[e.u], e.idx});
    }

  for (int i = 0; i < cidx; i++) {
    sort(all(tree[i]));
    tree[i].erase(unique(all(tree[i])), tree[i].end());
  }

  vi depth(cidx), first_occ(cidx), cnt_child(cidx);
  vii par(cidx, {-1, -1}), euler;
  vis = vb(cidx);
  function<void(int, int)> h = [&](int u, int p) {
    vis[u] = 1;
    first_occ[u] = euler.size();
    euler.push_back({depth[u], u});

    for (auto [v, i] : tree[u])
      if (v != p) {
        par[v] = {u, i};
        cnt_child[u]++;
        depth[v] = depth[u] + 1;
        h(v, u);
        euler.push_back({depth[u], u});
      }
  };
  vi roots;
  for (int i = 0; i < cidx; i++)
    if (!vis[i])
      roots.push_back(i), h(i, -1);

  ST s(euler.size(), euler);

  vi no_st(cidx), no_en(cidx);
  for (int i = 0; i < p; i++)
    if (cc_id[st[i]] != cc_id[en[i]]) {
      int st_cc = cc_id[st[i]], en_cc = cc_id[en[i]];
      int lca = s.query(first_occ[st_cc], first_occ[en_cc]);

      no_st[st_cc]++, no_en[en_cc]++;
      no_st[lca]--, no_en[lca]--;
    }

  function<void(int, int)> d = [&](int u, int p) {
    for (auto [v, i] : tree[u])
      if (v != p) {
        d(v, u);
        no_st[u] += no_st[v];
        no_en[u] += no_en[v];
      }
  };
  for (int root : roots)
    d(root, -1);

  for (int i = 0; i < cidx; i++) {
    auto [p, peid] = par[i];
    if (p < 0)
      continue;
    if (no_st[i]) {
      if (cc_id[eds[peid].u] == i)
        eds[peid].res = 0;
      else
        eds[peid].res = 1;
      continue;
    }
    if (no_en[i]) {
      if (cc_id[eds[peid].u] == i)
        eds[peid].res = 1;
      else
        eds[peid].res = 0;
    }
  }

  for (Edge &e : eds) {
    if (e.res == 2)
      cout << "B";
    else if (e.res == 0)
      cout << "R";
    else
      cout << "L";
  }
  cout << "\n";
}

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

  clock_t start = clock();

  int test_cases = 1;
  // cin >> test_cases;

  while (test_cases--)
    solve();

#ifdef DEBUG
  cerr << fixed << setprecision(10)
       << "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
       << "s\n";
#endif
  return 0;
}

Compilation message

oneway.cpp: In function 'int main()':
oneway.cpp:275:11: warning: unused variable 'start' [-Wunused-variable]
  275 |   clock_t start = clock();
      |           ^~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 456 KB Output is correct
4 Correct 2 ms 920 KB Output is correct
5 Correct 1 ms 840 KB Output is correct
6 Correct 1 ms 324 KB Output is correct
7 Correct 1 ms 852 KB Output is correct
8 Correct 1 ms 836 KB Output is correct
9 Correct 1 ms 328 KB Output is correct
10 Correct 1 ms 372 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 456 KB Output is correct
4 Correct 2 ms 920 KB Output is correct
5 Correct 1 ms 840 KB Output is correct
6 Correct 1 ms 324 KB Output is correct
7 Correct 1 ms 852 KB Output is correct
8 Correct 1 ms 836 KB Output is correct
9 Correct 1 ms 328 KB Output is correct
10 Correct 1 ms 372 KB Output is correct
11 Correct 42 ms 8236 KB Output is correct
12 Correct 53 ms 9620 KB Output is correct
13 Correct 62 ms 13012 KB Output is correct
14 Correct 79 ms 23508 KB Output is correct
15 Correct 58 ms 28248 KB Output is correct
16 Correct 127 ms 56424 KB Output is correct
17 Correct 90 ms 58496 KB Output is correct
18 Correct 99 ms 56404 KB Output is correct
19 Correct 90 ms 60024 KB Output is correct
20 Correct 40 ms 9588 KB Output is correct
21 Correct 43 ms 9676 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 456 KB Output is correct
4 Correct 2 ms 920 KB Output is correct
5 Correct 1 ms 840 KB Output is correct
6 Correct 1 ms 324 KB Output is correct
7 Correct 1 ms 852 KB Output is correct
8 Correct 1 ms 836 KB Output is correct
9 Correct 1 ms 328 KB Output is correct
10 Correct 1 ms 372 KB Output is correct
11 Correct 42 ms 8236 KB Output is correct
12 Correct 53 ms 9620 KB Output is correct
13 Correct 62 ms 13012 KB Output is correct
14 Correct 79 ms 23508 KB Output is correct
15 Correct 58 ms 28248 KB Output is correct
16 Correct 127 ms 56424 KB Output is correct
17 Correct 90 ms 58496 KB Output is correct
18 Correct 99 ms 56404 KB Output is correct
19 Correct 90 ms 60024 KB Output is correct
20 Correct 40 ms 9588 KB Output is correct
21 Correct 43 ms 9676 KB Output is correct
22 Correct 104 ms 60448 KB Output is correct
23 Correct 101 ms 58276 KB Output is correct
24 Correct 145 ms 58332 KB Output is correct
25 Correct 111 ms 64580 KB Output is correct
26 Correct 114 ms 59904 KB Output is correct
27 Correct 123 ms 58360 KB Output is correct
28 Correct 25 ms 6360 KB Output is correct
29 Correct 58 ms 10912 KB Output is correct
30 Correct 48 ms 11220 KB Output is correct
31 Correct 54 ms 11468 KB Output is correct
32 Correct 68 ms 27672 KB Output is correct