Submission #839203

#	Time	Username	Problem	Language	Result	Execution time	Memory
839203		asdfgrace	Tropical Garden (IOI11_garden)	C++17	100 / 100	3514 ms	74336 KiB

garden

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast,unroll-loops,O3")
#pragma GCC target("avx,avx2")
#include "garden.h"
#include "gardenlib.h"
using namespace std;

void count_routes(int N, int M, int P, int R[][2], int Q, int G[]) {
  const int INF = (int) 1e9;
  vector<vector<int>> edges(N);
  for (int i = 0; i < M; ++i) {
    edges[R[i][0]].push_back(R[i][1]);
    edges[R[i][1]].push_back(R[i][0]);
  }
  vector<int> next(2 * N, -1);
  for (int i = 0; i < N; ++i) {
    int x = edges[i][0];
    next[2 * i] = (i == edges[x][0] ? 2 * x + 1 : 2 * x);
    x = ((int) edges[i].size() == 1 ? edges[i][0] : edges[i][1]);
    next[2 * i + 1] = (i == edges[x][0] ? 2 * x + 1 : 2 * x);
  }
  vector<vector<int>> pred(2 * N);
  for (int i = 0; i < 2 * N; ++i) {
    pred[next[i]].push_back(i);
  }
  vector<bool> visited(2 * N, false), active(2 * N, false);
  vector<int> st, cyc_sz(2 * N, 0), cyc_dist(2 * N, INF), elem(2 * N, -1),
    cyc_root(2 * N, -1), cyc_id(2 * N, -1);
  int cycles = -1, start = 0;
  function<void(int)> dfs = [&](int node) {
    if (active[node]) {
      ++cycles;
      int sz = (int) st.size();
      int bgn = 0;
      while (st[bgn] != node) {
        ++bgn;
      }
      sz -= bgn;
      for (int i = bgn; i < (int) st.size(); ++i) {
        cyc_id[st[i]] = i - bgn;
        cyc_sz[st[i]] = sz;
        cyc_dist[st[i]] = 0;
        cyc_root[st[i]] = st[i];
        elem[st[i]] = cycles;
      }
    }
    if (visited[node]) {
      return;
    }
    visited[node] = true;
    active[node] = true;
    st.push_back(node);
    dfs(next[node]);
    active[node] = false;
    st.pop_back();
  };
  vector<vector<int>> anc(20, vector<int>(2 * N, -1));
  function<void(int, int)> tree_dfs = [&](int node, int root) -> void {
    for (auto x : pred[node]) {
      cyc_dist[x] = cyc_dist[node] + 1;
      anc[0][x] = node;
      cyc_root[x] = root;
      elem[x] = elem[root];
      tree_dfs(x, root);
    }
  };
  for (start = 0; start < 2 * N; start += 2) {
    if (!visited[start]) {
      dfs(start);
    }
  }
  for (int i = 0; i < 2 * N; ++i) {
    if (cyc_dist[i] == INF && cyc_dist[next[i]] == 0) {
      cyc_dist[i] = 1;
      anc[0][i] = next[i];
      cyc_root[i] = i;
      elem[i] = elem[next[i]];
      tree_dfs(i, i);
    }
  }
  for (int j = 1; j < 20; ++j) {
    for (int i = 0; i < 2 * N; ++i) {
      if (anc[j - 1][i] == -1) continue;
      anc[j][i] = anc[j - 1][anc[j - 1][i]];
    }
  }
  auto get = [&](int i, int k) {
    for (int j = 19; j >= 0; --j) {
      if (k >= 1 << j) {
        i = anc[j][i];
        k -= 1 << j;
      }
    }
    return i;
  };
  for (int j = 0; j < Q; ++j) {
    int k = G[j], cnt = 0;
    for (int i = 0; i < N; ++i) {
      for (int p = 2 * P; p <= 2 * P + 1; ++p) {
        int node = 2 * i, dist = 0;
        if (elem[node] != elem[p]) continue;
        if (cyc_dist[node] != 0 && cyc_dist[p] <= cyc_dist[node]
          && cyc_root[p] == cyc_root[node]) {
          dist = cyc_dist[node] - cyc_dist[p];
          if (dist == k && get(node, dist) == p) {
            ++cnt;
          }
          continue;
        } else if (cyc_dist[p] > cyc_dist[node] ||
          (cyc_dist[p] != 0 && cyc_root[p] != cyc_root[node])) {
          continue;
        } else if (cyc_dist[node] != 0) {
          dist += cyc_dist[node];
          node = next[cyc_root[node]];
        }
        dist += (cyc_id[p] >= cyc_id[node] ? cyc_id[p] - cyc_id[node]
          : cyc_sz[node] - cyc_id[node] + cyc_id[p]);
        if (k >= dist && dist % cyc_sz[node] == k % cyc_sz[node]) {
          ++cnt;
        } 
      }
    }
    answer(cnt);
  }
}

• Subtask 1: 49 / 49
• Subtask 2: 20 / 20
• Subtask 3: 31 / 31