cplib

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:heavy_check_mark: graph/dijkstra.cpp

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Code

#pragma once

#include "template.cpp"
#include "graph/graph.cpp"
#include "data-structure/binary-heap.cpp"

vector<ll> dijkstra(const Graph& graph, int start) {
  BinaryHeap<ll, greater<>> hp;
  vector<ll> dist(graph.size(), INF_LL);
  dist[start] = 0;
  hp.emplace(start, 0);

  while (not hp.empty()) {
    ll d = hp.top();
    int v = hp.top_index();
    hp.pop();
    if (dist[v] < d) continue;
    for (auto e : graph[v]) {
      if (chmin(dist[e.to], dist[v] + e.cost)) hp.prioritize(e.to, dist[e.to]);
    }
  }
  return dist;
}
#line 2 "graph/dijkstra.cpp"

#line 2 "template.cpp"

#ifndef LOCAL
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx")
#endif
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <functional>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using VI = vector<int>;
using VVI = vector<vector<int>>;
using VLL = vector<ll>;
using VVLL = vector<vector<ll>>;
using VB = vector<bool>;
using PII = pair<int, int>;
using PLL = pair<ll, ll>;
constexpr int INF = 1000000007;
constexpr ll INF_LL = 1'000'000'000'000'000'007;
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define newl '\n'

// loops rep(until) / rep(var, until) / rep(var, from, until) / repr (reversed order)
#define OVERLOAD3(_1, _2, _3, name, ...) name
#define rep(...) OVERLOAD3(__VA_ARGS__, REPEAT_FROM_UNTIL, REPEAT_UNTIL, REPEAT)(__VA_ARGS__)
#define REPEAT(times) REPEAT_CNT(_repeat, __COUNTER__, times)
#define REPEAT_CNT(_repeat, cnt, times) REPEAT_CNT_CAT(_repeat, cnt, times)
#define REPEAT_CNT_CAT(_repeat, cnt, times) REPEAT_FROM_UNTIL(_repeat ## cnt, 0, times)
#define REPEAT_UNTIL(name, times) REPEAT_FROM_UNTIL(name, 0, times)
#define REPEAT_FROM_UNTIL(name, from, until) for (int name = from, name ## __until = (until); name < name ## __until; name++)
#define repr(...) OVERLOAD3(__VA_ARGS__, REPR_FROM_UNTIL, REPR_UNTIL, REPEAT)(__VA_ARGS__)
#define REPR_UNTIL(name, times) REPR_FROM_UNTIL(name, 0, times)
#define REPR_FROM_UNTIL(name, from, until) for (int name = (until)-1, name ## __from = (from); name >= name ## __from; name--)

template <typename T, typename U>
bool chmin(T& var, U x) { if (var > x) { var = x; return true; } else return false; }
template <typename T, typename U>
bool chmax(T& var, U x) { if (var < x) { var = x; return true; } else return false; }
ll power(ll e, ll t, ll mod = INF_LL) {
  ll res = 1; for (; t; t >>= 1, (e *= e) %= mod) if (t & 1) (res *= e) %= mod; return res;
}
ll choose(ll n, int r) {
  chmin(r, n-r); if (r < 0) return 0; ll res = 1; rep(i, r) res *= n-i, res /= i+1; return res;
}
template <typename T, typename U> T divceil(T m, U d) { return (m + d - 1) / d; }
template <typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template <typename... Ts> auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v(ts...))>(a, make_v(ts...));
}

// debugging stuff
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wmisleading-indentation"
#define repi(it, ds) for (auto it = ds.begin(); it != ds.end(); it++)
class DebugPrint { public: template <typename T> DebugPrint& operator <<(const T& v) {
#ifdef LOCAL
    cerr << v;
#endif
return *this; } } debugos; template <typename T> DebugPrint& operator<<(DebugPrint& os, const
vector<T>& vec) { os << "{"; for (int i = 0; i < vec.size(); i++) os << vec[i] << (i + 1 ==
vec.size() ? "" : ", "); os << "}"; return os; } template <typename T, typename U> DebugPrint&
operator<<(DebugPrint& os, const map<T, U>& map_var) { os << "{"; repi(itr, map_var) { os << *
itr; itr++; if (itr != map_var.end()) os << ", "; itr--; } os << "}"; return os; } template <
typename T> DebugPrint& operator<<(DebugPrint& os, const set<T>& set_var) { os << "{"; repi(
itr, set_var) { os << *itr; itr++; if (itr != set_var.end()) os << ", "; itr--; } os << "}";
return os; } template <typename T, typename U> DebugPrint& operator<<(DebugPrint& os, const
pair<T, U>& p) { os << "(" << p.first << ", " << p.second << ")"; return os; } void dump_func(
) { debugos << newl; } template <class Head, class... Tail> void dump_func(Head &&head, Tail
&&... tail) { debugos << head; if (sizeof...(Tail) > 0) { debugos << ", "; } dump_func(forward
<Tail>(tail)...); }
#ifdef LOCAL
#define dump(...) debugos << "  " << string(#__VA_ARGS__) << ": " << "[" << to_string(__LINE__) \
<< ":" << __FUNCTION__ << "]" << newl << "    ", dump_func(__VA_ARGS__)
#else
#define dump(...) ({})
#endif
#pragma GCC diagnostic pop


#line 2 "graph/graph.cpp"

#line 4 "graph/graph.cpp"

struct Edge {
  int to; ll cost;
  Edge(int _to) : to(_to), cost(1) {}
  Edge(int _to, ll _cost) : to(_to), cost(_cost) {}
  operator int() const { return to; }
};

using Graph = vector<vector<Edge>>;
#line 2 "data-structure/binary-heap.cpp"

#line 4 "data-structure/binary-heap.cpp"

template <typename T, typename Compare = less<>>
class BinaryHeap {
 private:
  vector<T> data;
  vector<int> index, handle;
  const Compare comp;

 public:
  BinaryHeap(Compare comp_ = {}) : comp(comp_) {}
  template <typename Iter>
  BinaryHeap(Iter first, Iter last, Compare comp_ = {}) : comp(comp_) {
    data.insert(data.end(), first, last);
    index.resize(data.size());
    handle.resize(data.size());
    iota(all(index), 0);
    iota(all(handle), 0);
    repr(i, divceil(data.size(), 2)) pushdown(i);
  }

 private:
  void rotate(int i, int j) {
    swap(data[i], data[j]);
    swap(index[i], index[j]);
    swap(handle[index[i]], handle[index[j]]);
  }

  void pushup(int i) {
    int j;
    while (j = (i - 1) / 2, comp(data[j], data[i])) rotate(i, j), i = j;
  }

  void pushdown(int i) {
    int j;
    while (j = (i + 1) * 2, j < data.size()) {
      if (comp(data[j], data[j - 1])) j--;
      rotate(i, j), i = j;
    }
    j = i * 2 + 1;
    if (j < data.size() and comp(data[i], data[j])) rotate(i, j);
  }

 public:
  bool empty() { return data.empty(); }

  void push(int i, const T& v) { emplace(i, v); }
  void push(int i, T&& v) { emplace(i, move(v)); }

  template <typename... Args>
  void emplace(int i, Args&&... args) {
    if (i >= handle.size()) {
      int s = handle.size();
      handle.resize(i + 1);
      fill(handle.begin() + s, handle.end(), -1);
    }
    handle[i] = data.size();
    data.emplace_back(forward<Args>(args)...);
    index.push_back(i);
    pushup(handle[i]);
  }

  T& top() { return data[0]; }
  int top_index() { return index[0]; }

  void pop() { remove(0); }

  void remove(int i) {
    if (i != data.size() - 1) rotate(i, data.size() - 1);
    data.pop_back();
    handle[index.back()] = -1;
    index.pop_back();
    pushdown(i);
  }

  template <typename... Args>
  void prioritize(int i, Args&&... args) {
    if (i >= handle.size() or handle[i] == -1)
      emplace(i, forward<Args>(args)...);
    else {
      data[handle[i]] = T(forward<Args>(args)...);
      pushup(handle[i]);
      pushdown(handle[i]);
    }
  }
};
#line 6 "graph/dijkstra.cpp"

vector<ll> dijkstra(const Graph& graph, int start) {
  BinaryHeap<ll, greater<>> hp;
  vector<ll> dist(graph.size(), INF_LL);
  dist[start] = 0;
  hp.emplace(start, 0);

  while (not hp.empty()) {
    ll d = hp.top();
    int v = hp.top_index();
    hp.pop();
    if (dist[v] < d) continue;
    for (auto e : graph[v]) {
      if (chmin(dist[e.to], dist[v] + e.cost)) hp.prioritize(e.to, dist[e.to]);
    }
  }
  return dist;
}
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