Graph/bfs.hpp

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• Last update: 2020-11-05 12:15:41+09:00
• Include: #include "Graph/bfs.hpp"

Depends on

• Graph/graph.hpp

Code

#pragma once

#include "graph.hpp"

#include <queue>

template <class Cost>
std::vector<Cost> bfs(const Graph<Cost>& graph, int s) {
    std::vector<Cost> dist(graph.size(), -1);
    dist[s] = 0;
    std::queue<int> que;
    que.push(s);

    while (!que.empty()) {
        auto v = que.front();
        que.pop();

        for (const auto& e : graph[v]) {
            if (dist[e.dst] != -1) continue;
            dist[e.dst] = dist[v] + e.cost;
            que.push(e.dst);
        }
    }

    return dist;
}

#line 2 "Graph/bfs.hpp"

#line 2 "Graph/graph.hpp"

#include <vector>

template <class Cost = int>
struct Edge {
    int src, dst;
    Cost cost;

    Edge() = default;
    Edge(int src, int dst, Cost cost = 1)
        : src(src), dst(dst), cost(cost){};

    bool operator<(const Edge<Cost>& e) const { return cost < e.cost; }
    bool operator>(const Edge<Cost>& e) const { return cost > e.cost; }
};

template <class Cost = int>
struct Graph : public std::vector<std::vector<Edge<Cost>>> {
    using std::vector<std::vector<Edge<Cost>>>::vector;

    void span(bool direct, int src, int dst, Cost cost = 1) {
        (*this)[src].emplace_back(src, dst, cost);
        if (!direct) (*this)[dst].emplace_back(dst, src, cost);
    }
};
#line 4 "Graph/bfs.hpp"

#include <queue>

template <class Cost>
std::vector<Cost> bfs(const Graph<Cost>& graph, int s) {
    std::vector<Cost> dist(graph.size(), -1);
    dist[s] = 0;
    std::queue<int> que;
    que.push(s);

    while (!que.empty()) {
        auto v = que.front();
        que.pop();

        for (const auto& e : graph[v]) {
            if (dist[e.dst] != -1) continue;
            dist[e.dst] = dist[v] + e.cost;
            que.push(e.dst);
        }
    }

    return dist;
}

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