kyopro-lib-cpp

This documentation is automatically generated by online-judge-tools/verification-helper

View the Project on GitHub packer-jp/kyopro-lib-cpp

:heavy_check_mark: test/judge.yosupo.jp/Shortest_Path.0.test.cpp

Depends on

Code

#define PROBLEM "https://judge.yosupo.jp/problem/shortest_path"
#include "../../graph/dijkstra.hpp"

int main() {
    ll n, m, s, t;
    cin >> n >> m >> s >> t;
    dijkstra<ll_dijkstra> dij(n);
    while (m--) {
        int a, b, c;
        cin >> a >> b >> c;
        dij.add_edge(a, b, c);
    }
    auto [dist, prev] = dij.get(s);
    if (prev[t] == -1) {
        cout << -1 << endl;
        return 0;
    }
    vll vs{t};
    do {
        ll back = vs.back();
        vs.push_back(prev[back]);
    } while (vs.back() != s);
    reverse(all(vs));
    cout << dist[t] << " " << vs.size() - 1 << endl;
    for (ll i : rep(vs.size() - 1)) cout << vs[i] << " " << vs[i + 1] << endl;
}
#line 1 "test/judge.yosupo.jp/Shortest_Path.0.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/shortest_path"
#line 2 "graph/dijkstra.hpp"

#line 2 "template.hpp"

#include <bits/stdc++.h>
using namespace std;

#define all(a) begin(a), end(a)
#define rall(a) rbegin(a), rend(a)
#define uniq(a) (a).erase(unique(all(a)), (a).end())
#define t0 first
#define t1 second
using ll = long long;
using ull = unsigned long long;
using pll = pair<ll, ll>;
using vll = vector<ll>;
constexpr double pi = 3.14159265358979323846;
constexpr ll dy[9] = {0, 1, 0, -1, 1, 1, -1, -1, 0};
constexpr ll dx[9] = {1, 0, -1, 0, 1, -1, -1, 1, 0};
constexpr ll sign(ll a) { return (a > 0) - (a < 0); }
constexpr ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
constexpr ll cdiv(ll a, ll b) { return -fdiv(-a, b); }
constexpr ll pw(ll n) { return 1ll << n; }
constexpr ll flg(ll n) { return 63 - __builtin_clzll(n); }
constexpr ll clg(ll n) { return n == 1 ? 0 : flg(n - 1) + 1; }
constexpr ll safemod(ll x, ll mod) { return (x % mod + mod) % mod; }
template <typename T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
template <typename T> constexpr T sq(const T &a) { return a * a; }
template <typename T, typename U> constexpr bool chmax(T &a, const U &b) { return a < b ? a = b, true : false; }
template <typename T, typename U> constexpr bool chmin(T &a, const U &b) { return a > b ? a = b, true : false; }
template <typename T, typename U> ostream &operator<<(ostream &os, const pair<T, U> &a) {
    os << "(" << a.first << ", " << a.second << ")";
    return os;
}
template <typename T, typename U, typename V> ostream &operator<<(ostream &os, const tuple<T, U, V> &a) {
    os << "(" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ")";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const vector<T> &a) {
    os << "(";
    for (auto itr = a.begin(); itr != a.end(); ++itr) os << *itr << (next(itr) != a.end() ? ", " : "");
    os << ")";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &a) {
    os << "(";
    for (auto itr = a.begin(); itr != a.end(); ++itr) os << *itr << (next(itr) != a.end() ? ", " : "");
    os << ")";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &a) {
    os << "(";
    for (auto itr = a.begin(); itr != a.end(); ++itr) os << *itr << (next(itr) != a.end() ? ", " : "");
    os << ")";
    return os;
}
template <typename T, typename U> ostream &operator<<(ostream &os, const map<T, U> &a) {
    os << "(";
    for (auto itr = a.begin(); itr != a.end(); ++itr) os << *itr << (next(itr) != a.end() ? ", " : "");
    os << ")";
    return os;
}
#ifdef ONLINE_JUDGE
#define dump(...) (void(0))
#else
void debug() { cerr << endl; }
template <typename Head, typename... Tail> void debug(Head &&head, Tail &&... tail) {
    cerr << head;
    if (sizeof...(Tail)) cerr << ", ";
    debug(tail...);
}
#define dump(...) cerr << __LINE__ << ": " << #__VA_ARGS__ << " = ", debug(__VA_ARGS__)
#endif
struct rep {
    struct itr {
        ll v;
        itr(ll v) : v(v) {}
        void operator++() { ++v; }
        ll operator*() const { return v; }
        bool operator!=(itr i) const { return v < *i; }
    };
    ll l, r;
    rep(ll l, ll r) : l(l), r(r) {}
    rep(ll r) : rep(0, r) {}
    itr begin() const { return l; };
    itr end() const { return r; };
};
struct per {
    struct itr {
        ll v;
        itr(ll v) : v(v) {}
        void operator++() { --v; }
        ll operator*() const { return v; }
        bool operator!=(itr i) const { return v > *i; }
    };
    ll l, r;
    per(ll l, ll r) : l(l), r(r) {}
    per(ll r) : per(0, r) {}
    itr begin() const { return r - 1; };
    itr end() const { return l - 1; };
};
struct io_setup {
    static constexpr int PREC = 20;
    io_setup() {
        cout << fixed << setprecision(PREC);
        cerr << fixed << setprecision(PREC);
    };
} iOS;
#line 4 "graph/dijkstra.hpp"

template <typename S> struct dijkstra {
    using D = typename S::D;
    using C = typename S::C;
    struct edge {
        ll to;
        C cost;
    };
    vector<vector<edge>> g;
    dijkstra(ll n) : g(n) {}
    void add_edge(ll from, ll to, const C &cost) { g[from].push_back({to, cost}); }
    pair<vector<D>, vector<ll>> get(ll s, const D &base = D()) const {
        vector<D> dist(g.size(), S::inf());
        vector<ll> prev(g.size(), -1);
        using P = pair<D, ll>;
        priority_queue_rev<P> pq;
        dist[s] = base;
        pq.emplace(base, s);
        while (!pq.empty()) {
            auto [d, from] = pq.top();
            pq.pop();
            if (dist[from] < d) continue;
            for (auto [to, cost] : g[from]) {
                D nd = d + cost;
                if (nd < dist[to]) {
                    dist[to] = nd;
                    prev[to] = from;
                    pq.emplace(nd, to);
                }
            }
        }
        return {dist, prev};
    }
};

struct ll_dijkstra {
    using D = ll;
    using C = ll;
    static D inf() { return LLONG_MAX; }
};
#line 3 "test/judge.yosupo.jp/Shortest_Path.0.test.cpp"

int main() {
    ll n, m, s, t;
    cin >> n >> m >> s >> t;
    dijkstra<ll_dijkstra> dij(n);
    while (m--) {
        int a, b, c;
        cin >> a >> b >> c;
        dij.add_edge(a, b, c);
    }
    auto [dist, prev] = dij.get(s);
    if (prev[t] == -1) {
        cout << -1 << endl;
        return 0;
    }
    vll vs{t};
    do {
        ll back = vs.back();
        vs.push_back(prev[back]);
    } while (vs.back() != s);
    reverse(all(vs));
    cout << dist[t] << " " << vs.size() - 1 << endl;
    for (ll i : rep(vs.size() - 1)) cout << vs[i] << " " << vs[i + 1] << endl;
}
Back to top page