Submission #554841

#	Time	Username	Problem	Language	Result	Execution time	Memory
554841		Sam_a17	Evacuation plan (IZhO18_plan)	C++17	0 / 100	272 ms	52508 KiB

plan

#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 pf push_front
#define popf pop_front
#define popb pop_back

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> void print(set <T> v);
template <class T> void print(vector <T> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T, class V> void print(pair <T, V> p);
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(deque<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, class V> void print(unordered_map<T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'

// 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 != "" && str != "input") {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
  }

  if(str == "input") {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "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 = 1e5 + 10, inf = 1e8, LOG = sizeof(int) * 8 - 2;
int n, m, k, dist[N], vis[N], p[N], sz[N], depths[N];
int up[N][LOG], mini[N][LOG];
vector <pair<int, int>> adj[N], g[N];
vector <int> stations;
set    <int> st[N];

void djikstra() {
  for(int i = 1; i <= n; i++) {
    dist[i] = inf;
  }

  priority_queue<pair<int, int>> q;
  for(int i = 0; i < k; i++) {
    dist[stations[i]] = 0;
    q.push({0, stations[i]});
  }

  while(!q.empty()) {
    auto a = q.top();
    q.pop();

    if(vis[a.second]) continue;
    vis[a.second] = true;

    for(auto u: adj[a.second]) {
      if(dist[a.second] + u.second < dist[u.first]) {
        dist[u.first] = dist[a.second] + u.second;
        q.push({-dist[u.first], u.first});
      }
    }
  }
}

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

int merge(int x, int y) {
  x = find(x), y = find(y);
  if(x == y) {
    return 0;
  }
  if(sz[x] > sz[y]) {
    swap(x, y);
  }
  p[y] = x, sz[x] += sz[y];
  return 1;
}

void dfs(int node, int parent) {
  for(auto u: g[node]) {
    if(u.first == parent) continue;

    up[u.first][0] = node;
    mini[u.first][0] = u.second;
    for(int i = 1; i < LOG; i++) {
      up[u.first][i] = up[up[u.first][i - 1]][i - 1];
      mini[u.first][i] = min(mini[u.first][i - 1], mini[up[u.first][i - 1]][i - 1]);
    }
    depths[u.first] = depths[node] + 1;
    dfs(u.first, node);
  }
}

int lca(int a, int b) {
  if(a == b) {
    return 0;
  }

  if(depths[a] > depths[b]) {
    swap(a, b);
  }

  int delta = depths[b] - depths[a];
  int answ = inf;
  for(int i = 0; i < LOG; i++) {
    if(delta & (1 << i)) {
      answ = min(answ, mini[b][i]);
      b = up[b][i];
    }
  }

  if(a == b) {
    if(answ == inf) answ = 0;
    return answ;
  }

  for(int i = LOG - 1; i >= 0; i--) {
    if(up[a][i] != up[b][i]) {
      answ = min(answ, up[b][i]);
      a = up[a][i], b = up[b][i];
    }
  }

  if(answ == inf) answ = 0;
  return answ;
}

void solve_() {
  cin >> n >> m;
  for(int i = 1; i <= m; i++) {
    int a, b, c; cin >> a >> b >> c;
    adj[a].push_back({b, c});
    adj[b].push_back({a, c});
  }

  cin >> k;
  for(int i = 1; i <= k; i++) {
    int a; cin >> a;
    stations.push_back(a);
  }

  djikstra();

  vector < pair<int, pair<int, int> > > edge;
  for(int i = 1; i <= n; i++) {
    p[i] = i, sz[i] = 1;
  }

  for(int i = 1; i <= n; i++) {
    for (auto j: adj[i]) {
      edge.push_back({min(dist[i], dist[j.first]), {i, j.first}});
    }
  }

  sort(rall(edge));

  for(auto u: edge) {
    int a = u.second.first, b = u.second.second;
    int c = u.first;
    if(merge(a, b)) {
      g[a].push_back({b, c});
      g[b].push_back({a, c});
    }
  }

  dfs(1, 0);

  int q; cin >> q;
  while(q--) {
    int a, b; cin >> a >> b;
    printf("%d\n", lca(a, b));
  }
}

int main() {
  setIO("");

  auto solve = [&](int test_case)-> void {
    while(test_case--) {
      solve_();
    }
  };

  int test_cases = 1;
  solve(test_cases);

  return 0;
}

Compilation message (stderr)

plan.cpp: In function 'void setIO(std::string)':
plan.cpp:67:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   67 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:68:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:72:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
plan.cpp:73:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 12
• Subtask 4: 0 / 19
• Subtask 5: 0 / 46