Submission #265034

#	Time	Username	Problem	Language	Result	Execution time	Memory
265034		KoD	Bridges (APIO19_bridges)	C++11	73 / 100	3034 ms	6540 KiB

bridges

#include <iostream>
#include <algorithm>
#include <utility>
#include <cstdint>
#include <cstddef>
#include <vector>
#include <array>
#include <stack>

using i32 = int32_t;
using i64 = int64_t;
using u32 = uint32_t;
using u64 = uint64_t;

constexpr i32 inf32 = (i32(1) << 30) - 1;
constexpr i64 inf64 = (i64(1) << 62) - 1;

constexpr size_t BUCKET = 800;
constexpr size_t VERTICES = 50000;
constexpr size_t EDGES = 100000;
constexpr size_t QUERIES = 100000;

size_t N, M, Q, Step;

std::array<i32, VERTICES> parent;

std::array<i32, EDGES> U, V, C;
std::array<bool, EDGES> Static;

struct Query { i32 type, idx, weight; };
std::array<Query, QUERIES> Qs;
std::vector<i32> static_query, dynamic_query;
std::array<i32, QUERIES> answer;

i32 find(i32 u) {
  while (parent[u] >= 0) {
    u = parent[u];
  }
  return u;
}

void merge(i32 u, i32 v) {
  u = find(u);
  v = find(v);
  if (u == v) {
    return;
  }
  if (parent[u] > parent[v]) {
    std::swap(u, v);
  }
  parent[u] += parent[v];
  parent[v] = u;
}

void dfs(const std::vector<i32> &query, const size_t ans, const size_t cur) {
  if (cur == query.size()) {
    answer[ans] = -parent[find(Qs[ans].idx)];
    return;
  }
  if (C[Qs[query[cur]].idx] < Qs[ans].weight) {
    dfs(query, ans, cur + 1);
    return;
  }
  i32 u = find(U[Qs[query[cur]].idx]);
  i32 v = find(V[Qs[query[cur]].idx]);
  if (u == v) {
    dfs(query, ans, cur + 1);
    return;
  }
  if (parent[u] > parent[v]) {
    std::swap(u, v);
  }
  const i32 a = parent[u];
  const i32 b = parent[v];
  parent[u] += parent[v];
  parent[v] = u;
  dfs(query, ans, cur + 1);
  parent[u] = a;
  parent[v] = b;
}

int main() {
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(nullptr);
  std::cin >> N >> M;
  for (size_t i = 0; i < M; ++i) {
    std::cin >> U[i] >> V[i] >> C[i];
    --U[i]; --V[i];
  }
  std::cin >> Q;
  Step = (Q + BUCKET - 1) / BUCKET;
  for (size_t i = 0; i < Q; ++i) {
    std::cin >> Qs[i].type >> Qs[i].idx >> Qs[i].weight;
    --Qs[i].idx;
  }
  std::fill(Static.begin(), Static.end(), true);
  static_query.reserve(M + BUCKET);
  dynamic_query.reserve(BUCKET);
  for (size_t step = 0; step < Step; ++step) {
    std::fill(parent.begin(), parent.begin() + N, -1);
    const size_t first = step * BUCKET;
    const size_t last = std::min((step + 1) * BUCKET, Q);
    for (size_t i = first; i < last; ++i) {
      if (Qs[i].type == 1) {
        Static[Qs[i].idx] = false;
        dynamic_query.push_back((i32) i);
      }
      else {
        static_query.push_back(-((i32) i + 1));
      }
    }
    for (size_t i = 0; i < M; ++i) {
      if (Static[i]) {
        static_query.push_back((i32) i);
      }
    }
    std::sort(static_query.begin(), static_query.end(), [](i32 i, i32 j) {
      if (i >= 0 && j >= 0) {
        return C[i] > C[j];
      }
      else if (i >= 0) {
        if (C[i] == Qs[-(j + 1)].weight) {
          return true;
        }
        return C[i] > Qs[-(j + 1)].weight;
      }
      else if (j >= 0) {
        if (Qs[-(i + 1)].weight == C[j]) {
          return false;
        }
        return Qs[-(i + 1)].weight > C[j];
      }
      else {
        return Qs[-(i + 1)].weight > Qs[-(j + 1)].weight;
      }
    });
    for (auto i: static_query) {
      if (i >= 0) {
        merge(U[i], V[i]);
      }
      else {
        i = -(i + 1);
        std::stack<std::pair<i32, i32>> fix;
        for (auto j: dynamic_query) {
          if (j > i) {
            break;
          }
          fix.emplace(Qs[j].idx, C[Qs[j].idx]);
          C[Qs[j].idx] = Qs[j].weight;
        }
        dfs(dynamic_query, i, 0);
        while (!fix.empty()) {
          C[fix.top().first] = fix.top().second;
          fix.pop();
        }
      }
    }
    for (size_t i = first; i < last; ++i) {
      if (Qs[i].type == 1) {
        C[Qs[i].idx] = Qs[i].weight;
        Static[Qs[i].idx] = true;
      }
    }
    static_query.clear();
    dynamic_query.clear();
  }
  for (auto x: answer) {
    if (x != 0) {
      std::cout << x << '\n';
    }
  }
  return 0;
}

• Subtask 1: 13 / 13
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 14 / 14
• Subtask 5: 13 / 13
• Subtask 6: 0 / 27