src/dijkstra.hpp

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Last update: 2020-11-26 22:58:46+09:00
Include: #include "src/dijkstra.hpp"

Depends on

src/template.hpp

Verified with

test/dijkstra.test.cpp

Code

#pragma once
#include "template.hpp"

ll INF = 1LL<<60;

vl dijkstra(ll n, ll s, vector<vector<pl>> G) {
  priority_queue<pl, vector<pl>, greater<pl>> que;
  vl d(n, INF);
  d[s] = 0;
  que.push(pl(0, s));

  while(!que.empty()) {
    pl p = que.top();
    que.pop();
    ll v = p.second;
    if (d[v] < p.first) continue;
    for (auto&& e : G[v]) {
      if (d[e.first] > d[v] + e.second) {
        d[e.first] = d[v] + e.second;
        que.push(pl(d[e.first], e.first));
      }
    }
  }
  return d;
}

#line 2 "src/template.hpp"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pl = pair<ll, ll>;
using vl = vector<ll>;
#define rep(i, n) for(ll i = 0; i < (ll)n; i++)
#define rep3(i, l, r) for(ll i = l; i < (ll)r; i++)
#define per(i, n) for(ll i = (ll)n-1; i >= 0; i--)
#define per3(i, l, r) for(ll i = (ll)r-1; i >= (ll)l; i--)
#define all(v) begin(v), end(v)
#define rall(v) rbegin(v), rend(v)
template<class T, class U> inline void cmax(T &a, U b) { if (a < b) a = b; }
template<class T, class U> inline void cmin(T &a, U b) { if (a > b) a = b; }
constexpr char el = '\n';
template<class T, class U> ostream &operator<<(ostream &os, const pair<T, U> &p) { os << p.first << " " << p.second; return os; }
template<class T, class U> istream &operator>>(istream &is, pair<T, U> &p) { is >> p.first >> p.second; return is; }
template<class T> ostream &operator<<(ostream &os, const vector<T> &v) { rep(i, v.size()) os << v[i] << (i+1 != (ll)v.size() ? " " : ""); return os; }
template<class T> istream &operator>>(istream &is, vector<T> &v) { for(T &i : v) is >> i; return is; }
struct IoSetup {
  IoSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(15); }
} io_setup;
#line 3 "src/dijkstra.hpp"

ll INF = 1LL<<60;

vl dijkstra(ll n, ll s, vector<vector<pl>> G) {
  priority_queue<pl, vector<pl>, greater<pl>> que;
  vl d(n, INF);
  d[s] = 0;
  que.push(pl(0, s));

  while(!que.empty()) {
    pl p = que.top();
    que.pop();
    ll v = p.second;
    if (d[v] < p.first) continue;
    for (auto&& e : G[v]) {
      if (d[e.first] > d[v] + e.second) {
        d[e.first] = d[v] + e.second;
        que.push(pl(d[e.first], e.first));
      }
    }
  }
  return d;
}