graph/warshallfloydrestore.hpp

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• Last update: 2025-05-09 08:40:27+00:00
• Include: #include "graph/warshallfloydrestore.hpp"

Depends on

• graph/graphtemplate.hpp

Code

#pragma once
#include "graphtemplate"
#include <bits/stdc++.h>
using namespace std;
vector<vector<int>> warshallfloydrestore_p;
vector<vector<bool>> warshallfloydrestore_unreachable;
// ワーシャルフロイド法で求めた最短経路の復元 O(n^3)
template<class T = int, bool directed = false, bool weighted = true>
vector<T> warshallfloydrestorebuild(graph<T, directed, weighted>& g, int from, int to) {
    d = vector<vector<int>>(g.size(), vector<int>(g.size(), numeric_limits<int>::max()));
    warshallfloydrestore_p = vector<vector<int>>(g.size(), vector<int>(g.size(), -1));
    for (int i=0; i<g.size(); i++) {
        d[i][i] = 0;
        for (auto& _e : g[i]) {
            d[i][_e.to] = _e.cost;
            warshallfloydrestore_p[i][_e.to] = i;
        }
    }
    for (int k=0; k<g.size(); k++) {
        for (int i=0; i<g.size(); i++) {
            for (int j=0; j<g.size(); j++) {
                if (d[i][k] < numeric_limits<int>::max()/2 && d[k][j] < numeric_limits<int>::max()/2) {
                    if (d[i][j] > d[i][k] + d[k][j]) {
                        d[i][j] = d[i][k] + d[k][j];
                        warshallfloydrestore_p[i][j] = k;
                    }
                }
            }
        }
    }
    warshallfloydrestore_unreachable = vector<vector<bool>>(g.size(), vector<bool>(g.size(), false));
    for (int i=0; i<g.size(); i++) {
        for (int j=0; j<g.size(); j++) {
            if (d[i][j] == numeric_limits<int>::max()) {
                warshallfloydrestore_unreachable[i][j] = true;
            }
        }
    }
    return d[from][to];
}
// ワーシャルフロイド法で求めた最短経路の復元 O(n)
vector<int> warshallfloydrestore(int from, int to) {
    vector<int> path;
    if (warshallfloydrestore_unreachable[from][to]) return path;
    for (int i=to; i!=from; i=warshallfloydrestore_p[from][i]) path.push_back(i);
    path.push_back(from);
    reverse(path.begin(), path.end());
    return path;
}

#line 2 "graph/graphtemplate.hpp"
#include<bits/stdc++.h>
using namespace std;
// 辺の構造体 edge(from, to, cost, id)
template<class T = int>
struct edge {
    int from, to;
    T cost;
    int id;
};
// 頂点の構造体 vector<edge<T>>
template<class T = int>
using edges = vector<edge<T>>;
// グラフの構造体 graph<T, directed, weighted> 
template <class T = int, bool directed = false, bool weighted = false>
struct graph {
    bool isdirected, isweighted;
    edges<T> _edges;
    vector<edges<T>> data;
    T sumcost;
    graph() = default;
    // 頂点数 n のグラフを作成する
    graph(int n) : isdirected(directed), isweighted(weighted), data(n), sumcost(T{}) {}
    // from から to へ辺を追加する
    void add_edge(int from, int to, T cost = 1, int id = -1) {
        if (id == -1) id = _edges.size();
        data[from].push_back(edge<T>(from, to, cost, id));
        _edges.push_back(edge<T>(from, to, cost, id));
        if (!isdirected) {
            data[to].push_back(edge<T>(to, from, cost, id));
        }
        sumcost += cost;
    }
    // 辺を追加する
    void add_edge(edge<T> _e) {
        add_edge(_e.from, _e.to, _e.cost, _e.id);
    }
    // 標準入力から辺を読み込む
    void read(int m, int indexed = 1) {
        for (int i=0; i<m; i++) {
            int from, to;
            T cost = 1;
            cin >> from >> to;
            if (isweighted) cin >> cost;
            add_edge(from - indexed, to - indexed, cost);
        }
    }
    // 頂点数を返す
    int size() {
        return data.size();
    }
    // 頂点を返す
    edges<T> operator[](int k) {
        return data[k];
    }
    vector<int> path_to_vertex(edges<T>& _e) {
        vector<int> re;
        if (_e.size() == 0) {
            return re;
        }
        if (_e.size() == 1) {
            re.push_back(_e[0].from);
            re.push_back(_e[0].to);
            return re;
        }
        int x=_e[0].from,y=_e[0].to;
        if (x==_e[1].to || x == _e[1].from) swap(x, y);
        re.push_back(x);
        for (int i=1; i<_e.size(); i++) {
            re.push_back(y);
            x = _e[i].to;
            if (x == y) x = _e[i].from;
            swap(x, y);
        }
        return re;
    }
    edges<T> vetex_to_path (vector<int>& v){
        edges<T> re;
        for (int i=0; i+1<v.size(); i++) {
            for (auto& _e : this[v[i]]) {
                if (_e.to == v[i+1]) {
                    re.push_back(_e);
                    break;
                }
            }
        }
        return re;
    }
};
#line 4 "graph/warshallfloydrestore.hpp"
using namespace std;
vector<vector<int>> warshallfloydrestore_p;
vector<vector<bool>> warshallfloydrestore_unreachable;
// ワーシャルフロイド法で求めた最短経路の復元 O(n^3)
template<class T = int, bool directed = false, bool weighted = true>
vector<T> warshallfloydrestorebuild(graph<T, directed, weighted>& g, int from, int to) {
    d = vector<vector<int>>(g.size(), vector<int>(g.size(), numeric_limits<int>::max()));
    warshallfloydrestore_p = vector<vector<int>>(g.size(), vector<int>(g.size(), -1));
    for (int i=0; i<g.size(); i++) {
        d[i][i] = 0;
        for (auto& _e : g[i]) {
            d[i][_e.to] = _e.cost;
            warshallfloydrestore_p[i][_e.to] = i;
        }
    }
    for (int k=0; k<g.size(); k++) {
        for (int i=0; i<g.size(); i++) {
            for (int j=0; j<g.size(); j++) {
                if (d[i][k] < numeric_limits<int>::max()/2 && d[k][j] < numeric_limits<int>::max()/2) {
                    if (d[i][j] > d[i][k] + d[k][j]) {
                        d[i][j] = d[i][k] + d[k][j];
                        warshallfloydrestore_p[i][j] = k;
                    }
                }
            }
        }
    }
    warshallfloydrestore_unreachable = vector<vector<bool>>(g.size(), vector<bool>(g.size(), false));
    for (int i=0; i<g.size(); i++) {
        for (int j=0; j<g.size(); j++) {
            if (d[i][j] == numeric_limits<int>::max()) {
                warshallfloydrestore_unreachable[i][j] = true;
            }
        }
    }
    return d[from][to];
}
// ワーシャルフロイド法で求めた最短経路の復元 O(n)
vector<int> warshallfloydrestore(int from, int to) {
    vector<int> path;
    if (warshallfloydrestore_unreachable[from][to]) return path;
    for (int i=to; i!=from; i=warshallfloydrestore_p[from][i]) path.push_back(i);
    path.push_back(from);
    reverse(path.begin(), path.end());
    return path;
}

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