2021-1 用符号作为顶点名的图的API c++实现

输入格式

不需要知道边数，也没有直接给出顶点数。但是，通过两次扫描文件routes.txt，建立

• 符号表 Sting -> id 从【机场名】找到标志符【ID】
• 反向索引，从【ID】 找到【机场名】，即数组keys[]
• 存储【ID】的无向图

API

SymbolGraph.h

头文件见 Graph.h Paths.h

#pragma once
#include<map>
#include<sstream> 
#include"Graph.h"
#include"Paths.h"

/****************如无必要，勿增实体********************/
class SymbolGraph
{
    
    
public:
	SymbolGraph() {
    
    }
	SymbolGraph(string file, char sp);


	bool contains(string key) {
    
    
		return m_keyToID->find(key) != m_keyToID->end();
	}

	int index(string key) {
    
    
		return m_keyToID->at(key);
	}

	string name(int idx) {
    
    
		return m_keys->at(idx);
	}

	Graph* G() {
    
    
		return m_graph;
	}
private:
	map<string, int>* m_keyToID = nullptr;//键值-> ID
	vector<string>* m_keys = nullptr;//ID -> 键值
	Graph* m_graph = nullptr;

	vector<string>* split(string s, char sep);
};

void degreeOfSeparation(string file, string goalStr);
void testSymbolGraph();

SymbolGraph.cpp

 #include "SymbolGraph.h"

#define out(x) cout<<x<<" "
#define hh printf_s("\n")//换行

/*
* 要求文件里面的边只出现一次,即无向图，添加边时自动完成from->to to->from
* 格式：起点 邻接点1 邻接点2 邻接点3 ~
*/
SymbolGraph::SymbolGraph(string file, char sp)
{
    
    
    m_keyToID = new map<string, int>();

    ifstream stream(file, ios::in);
    string lineStr = "";
    while (getline(stream, lineStr)) {
    
    
        vector<string>* tmp = split(lineStr, sp);

        int n = tmp->size();
        for (int i = 0; i < n; i++)
        {
    
    
            if (m_keyToID->find(tmp->at(i)) == m_keyToID->end()) {
    
    
                m_keyToID->emplace(tmp->at(i), m_keyToID->size());
            }
        }
    }

    //构造键值表
    int v = m_keyToID->size();
    m_keys = new vector<string>(v);
    for (auto it = m_keyToID->begin(); it != m_keyToID->end(); ++it) {
    
    
        m_keys->at(it->second) = it->first;
    }

    //初始化顶点
    m_graph = new Graph(v);

    //添加边
    ifstream in(file, ios::in);
    while (getline(in, lineStr)) {
    
    
        vector<string>* tmp = split(lineStr, sp);
        int n = tmp->size();
        int v = m_keyToID->at(tmp->at(0));
        for (int i = 1; i < n; i++)
        {
    
    
            int w = m_keyToID->at(tmp->at(i));
            m_graph->addEdge(v, w);//添加无向边
        }
    }


}

vector<string>* SymbolGraph::split(string s, char sep)
{
    
    
    istringstream iss(s);
    vector<string>* res = new vector<string>();
    string buffer;
    while (getline(iss, buffer, sep)) {
    
    
        res->push_back(buffer);
    }
    return res;
}

void degreeOfSeparation(string file, string startName,char sp)
{
    
    
    SymbolGraph* sg = new SymbolGraph(file, sp);
    Graph* graph = sg->G();

    if (!sg->contains(startName)) {
    
    
        out(startName), out(" not in dataBase."), hh;
        return;
    }

    int s = sg->index(startName);
    Paths path(*graph, s);//默认是广度优先搜索
   

    out("input search name, input q to quit.\n");
    string next = "";
    while (true) {
    
    
        getline(cin,next);
        if (next == "q") break;
        if (sg->contains(next)) {
    
    
            int t = sg->index(next);
            if (path.hasPathto(t)) {
    
    
                for (auto id :path.pathTo(t)) {
    
    
                    out(" "), out(sg->name(id)), hh;
                }
            }
            else {
    
    
                out("Not connected");
            }
        }
        else {
    
    
            out("Not in dataBase.");
        }
        hh;
    }
}


void testSymbolGraph()
{
    
    
    //degreeOfSeparation("routes.txt", "JFK",' ');
    degreeOfSeparation("movies.txt", "Tin Men (1987)",'/');
}

routes.txt

LAX LAS PHX
LAS PHX DEN
PHX DEN ORD DFW
DEN ORD
ORD DFW HOU ATL JFK
DFW HOU
HOU ATL MCO
ATL MCO JFK
MCO JFK

示例

文本下载movies.txt