臨時保存leetcode單詞接龍，有點問題

#include<iostream>
#include<vector>
#include<list>
#include<unordered_map>
#include<unordered_set>
#include <string>
#include<functional>
#include<string.h>
#include<queue>

using namespace std;
class Edge;

class Node ///<節點
{
public:
	string value;//權值
    int in;//入度
    int out;//出度
    list<Edge> edge;//出的邊
    list<Node> nextnode;//出的邊連的節點
    Node(string valuee)
    {
        value = valuee;
        in = 0;
        out = 0;
    }
};

class Edge ///<邊
{
public:
    string weight;//權重
    Node *from;//有向圖的起點
    Node *to;//有向圖的終點
    int num;
    Edge(string weightt, Node *fromm, Node *too)
    {
        weight = weightt;
        from = fromm;
        to = too;
        num = -1;
    }
};

struct func  //hash 函數
{
    size_t operator()(const Edge a) const
    {
		return ((hash<string>()(a.weight) 
			^ (hash<Node*>()(a.from) << 1)) >> 1)
			^ (hash<Node*>()(a.to) << 1);
    }
};

struct cmp_fun //比較函數 ==
{
    bool operator()(const Edge &a, const Edge &b) const
    {
         return memcmp(&a, &b, sizeof(a)) == 0 ? true:false;
    }
};

class Graph//完整的圖結構
{
public:
    unordered_map<string, Node>node;
    unordered_set<Edge, func,cmp_fun>edge;
};

Graph graph;

void ReadGraph(vector<vector<string>>a)//讀圖程序
{
    int n = a.size();
    for (int i = 0; i<n; ++i)
    {
        string weight = a[i][0];
        string from = a[i][1];
        string to = a[i][2];


        ///<下面兩行代碼過後不管from和to是否出現過就都有了
        if (graph.node.find(from) == graph.node.end())//如果from點從沒在哈希中出現過就加入
            graph.node.insert(pair<string, Node>(from, Node(from)));
        if (graph.node.find(to) == graph.node.end())//如果to點從沒在哈希中出現過就加入
            graph.node.insert(pair<string, Node>(to, Node(to)));

        Node* p_fromNode = &graph.node.find(from)->second;//在哈希表中提出from點
        Node* p_toNode   = &graph.node.find(to)->second;//提出to點

        p_fromNode->nextnode.push_back(*p_toNode);//from節點的next節點是to
        ++p_fromNode->out;//from的出度++
        ++p_toNode->in;//to節點的入度++

        Edge newedge = Edge(weight, p_fromNode, p_toNode);//建立一條邊
		p_fromNode->edge.push_back(newedge);//把這條邊加入到from點的邊集中
        graph.edge.insert(newedge);//把這條邊加入到圖中
    }
}

int bfs(Graph graph, string beginWord, string endWord)
{
	queue<pair<string,int> >a;
	a.push(pair<string,int>(beginWord,1));
	unordered_set<string>b;

	int ret=0;
	while(!a.empty())
	{
		pair<string,int>temp = a.front();
		a.pop();
		if(b.end() == b.find(temp.first)) ///<沒有訪問過這個節點
		{
			b.insert(temp.first);
			auto it = graph.node.find(temp.first); 
			if(it == graph.node.end()) ///<找到的節點，任何一個節點的入度和出度都不會等於0,除非不是連通圖
				break;
			auto node_list = it->second.nextnode;
			for(auto it1=node_list.begin(); node_list.end() != it1; ++it1)///直接遍歷鏈表
			{
				if(endWord==it1->value )
				{
					ret = temp.second;
					return ret/2+1;
				}
				if(b.end() == b.find(it1->value))
					a.push(pair<string,int>(it1->value,temp.second+1));
			}
		}
	}
	return 0;
}

int ladderLength(string beginWord, string endWord, vector<string>& wordList) 
{
	wordList.push_back(beginWord);
//	wordList.push_back(endWord);
	vector<vector<string> >a;
	for(int i=0;i<(int)wordList.size();++i)
	{
		vector<string>temp(3);
		temp[0]="0";
		for(int j=0;j<3;++j)
		{
			string from = wordList[i];	
			string to = from;

			to[j]='*';
			temp[1]=from;
			temp[2]=to;
			a.push_back(temp);

			temp[1]=to;
			temp[2]=from;
			a.push_back(temp);
		}
	}
    ReadGraph(a);
	return bfs(graph,beginWord,endWord);
}
int main(void)
{
	string x[]={"most","mist","miss","lost","fist","fish"};
	vector<string> b(begin(x),end(x));

	cout<<	ladderLength("lost","miss",b)<<endl;

    return 0;
}