Submission #673717

#	Time	Username	Problem	Language	Result	Execution time	Memory
673717		Sam_a17	Bridges (APIO19_bridges)	C++17	100 / 100	2053 ms	9712 KiB

bridges

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;
 
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
 
#define sz(x) (int)x.size()
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define blt __builtin_popcount
 
#define pb push_back
#define popf pop_front
#define popb pop_back
#define ld long double
 
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
 
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
 
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
 
// for random generations
// mt19937 myrand(chrono::steady_clock::now().time_since_epoch().count());
mt19937 myrand(373);
 
// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
 
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();
 
  if(str == "input") {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
  } else {
    // freopen("skis.in", "r", stdin);
    // freopen("skis.out", "w", stdout);
  }
}
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int N = 2e5 + 10, S = 800;
vector<pair<long long, pair<long long, long long>>> change_edges;
vector<pair<pair<long long, long long>, long long>> queries;
vector<pair<pair<long long, long long>, pair<long long, long long>>> edges, new_edges, sorted_edges;
int n, m, p[N], sz[N], comp, ans[N], t = 0, ind[N];
bool is_type_2[N];
vector<int> lst;

stack<pair<pair<int, int>, pair<int, int>>> stuck;

// dsu
void init() {
  t = 0;
  lst.clear();
  for(int i = 1; i <= n; i++) {
    p[i] = i, sz[i] = 1;
  }
  while(!stuck.empty()) stuck.pop();
}

int find(int a) {
  if(a != p[a]) {
    return find(p[a]);
  }
  return p[a];
}

int same(int a, int b) {
  if(find(a) == find(b)) {
    return 1;
  }
  return 0;
}
 
void merge(int a, int b, int t) {
  a = find(a), b = find(b);
  if(a == b) {
    return;
  }
 
  if(sz[a] > sz[b]) {
    swap(a, b);
  }
 
  p[a] = b, sz[b] += sz[a];
  comp--;
  stuck.push({{t, comp}, {a, b}});
}

void rollback(int t) {
  while (!stuck.empty() && stuck.top().first.first > t) {
    auto u = stuck.top().second;
    int a = u.second, b = u.first;
    sz[a] -= sz[b], p[b] = b;
    comp++;
    stuck.pop();
  }
}

void compute() {
  sort(rall(queries));

  vector<bool> vis(m);
  
  vector<int> changed;
  for(auto i: change_edges) {
    int curr = i.second.first;
    if(!vis[curr]) {
      changed.push_back(curr);
    }
    vis[curr] = true;
  }

  init();
  int it = 0;
  for(int i = 0; i < sz(queries); i++) {

    while(it < m && edges[it].first.first >= queries[i].first.first) {
      if(!vis[edges[it].first.second]) {
        merge(edges[it].second.first, edges[it].second.second, t++);
      }
      it++;
    }

    // persist
    lst.push_back(t++);

    //
    int pos = queries[i].second;
    for(int j = 0; j < sz(change_edges); j++) {
      if(change_edges[j].first < pos) {
        int curr = ind[change_edges[j].second.first];
        new_edges[curr].first.first = change_edges[j].second.second;
      }
    }

    for(auto j: changed) {
      int curr = ind[j];
      if(new_edges[curr].first.first >= queries[i].first.first) {
        merge(new_edges[curr].second.first, new_edges[curr].second.second, t++);
      }
      new_edges[curr].first.first = edges[curr].first.first;
    }
    
    ans[queries[i].second] = sz[find(queries[i].first.second)];
  
    //
    rollback(lst.back());
    lst.pop_back();
  }

  //
  for(auto i: change_edges) {
    int curr = ind[i.second.first]; 
    edges[curr].first.first = i.second.second;
  }

  sort(rall(edges));
  new_edges = edges;

  for(int i = 0; i < m; i++) {
    ind[edges[i].first.second] = i;
  }
}

void solve_() {
  cin >> n >> m;

  for(int i = 1; i <= m; i++) {
    long long u, v, d; cin >> u >> v >> d;
    edges.push_back({{d, i - 1}, {u, v}});
  }
  sort(rall(edges));
  new_edges = edges;

  for(int i = 0; i < m; i++) {
    ind[edges[i].first.second] = i;
  }

  int q; cin >> q;
  for(int i = 1; i <= q; i++) {
    int type; cin >> type;
    long long x, y; cin >> x >> y;
    if(type == 1) {
      change_edges.push_back({i, {x - 1, y}});
    } else {
      queries.push_back({{y, x}, i});
      is_type_2[i] = true;
    }

    if(sz(change_edges) + sz(queries) == S) {
      compute();
      change_edges.clear();
      queries.clear();
    }
  }

  if(sz(change_edges) + sz(queries) > 0) {
    compute();
    change_edges.clear();
    queries.clear();
  }

  for(int i = 1; i <= q; i++) {
    if(is_type_2[i]) {
      cout << ans[i] << '\n';
    }
  }
}
 
int main() {
  setIO();
 
  auto solve = [&](int test_case)-> void {
    for(int i = 1; i <= test_case; i++) {
      // cout << "Case #" << i << ": ";
      solve_();
    }
  };
 
  int test_cases = 1;
  // cin >> test_cases;
  solve(test_cases);
 
  return 0;
} 

Compilation message (stderr)

bridges.cpp: In function 'void setIO(std::string)':
bridges.cpp:69:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
bridges.cpp:70:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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