图的拓扑序列（BFS_如果节点带着入度信息）

本文主要是介绍图的拓扑序列（BFS_如果节点带着入度信息），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

 way：找入度为0的节点删除，减少其他节点的入度，继续找入度为0的节点，直到删除完所有的图节点。（遍历node的neighbors就能得到neighbors的入度信息）

#include<iostream>
#include<vector>
#include<map>
#include<set>
#include<queue>
using namespace std;//边结构的描述
class Edge
{
public://边的起始节点Node *from;//边的终点节点Node *to;//边的权重int weight;
public:Edge(Node *from, Node *to, int weight){this->from = from;this->to = to;this->weight = weight;}
};//点结构的描述
class Node
{
public://编号值int value;//入度int in;//出度int out;//邻接的点vector<Node*> nexts;//邻接的边vector<Edge*> edges;
public:Node(){}Node(int value){this->value = value;in = 0;out = 0;}
};//图结构的描述
class Graph
{
public:map<int, Node*> nodes;set<Edge*> edges;Graph(){}
};//利用边结构描述的图来构建图结构
//[0,7,5]   [from,to,weight]
//[0,1,3]   [from,to,weight]
Graph* createGraph(vector<vector<int>> matrix)
{Graph *graph = new Graph();int m = matrix.size();for(int i=0; i<m; i++){int from = matrix[i][0];int to = matrix[i][1];int weight = matrix[i][2];//将起点结构放到图里面if(!graph->nodes.count(from)){Node *fromNode =new Node(from);graph->nodes[from] = fromNode;}//将终点结构放到图里面if(!graph->nodes.count(to)){Node *toNode=new Node(to);graph->nodes[to] = toNode;}//将起点和终点的边结构也放到图里面(点可能已经存在过,边一定是新的)Node *fromNode = graph->nodes[from];Node *toNode = graph->nodes[to];Edge *newEdge = new Edge(fromNode, toNode, weight);fromNode->nexts.push_back(toNode);fromNode->edges.push_back(newEdge);fromNode->out++;toNode->in++;graph->edges.insert(newEdge);}return graph;
}vector<Node*> topSort(Graph *graph)
{//收集节点入度映射，将0入度放入que中map<Node*,int>indegreeMap;queue<Node*>zeroQue;for(auto pa:graph->nodes){indegreeMap[pa.second]=pa.second->in;if(indegreeMap[pa.second]==0){zeroQue.push(pa.second);}}vector<Node*>result;//开始按入度为0删除节点，同时减少其他节点入度，删除入度为0...while(!zeroQue.empty()){Node *cur=zeroQue.front();zeroQue.pop();result.push_back(cur);for(auto next: cur->nexts){indegreeMap[next]=indegreeMap[next]-1;if(indegreeMap[next]==0){zeroQue.push(next);}}}return result;
}

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