多段图问题（图的邻接表）

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/**********************************//*          多段图问题            *//*求源点到汇点的最小花费及最短路径*//**********************************/#include<iostream>#include<stdlib.h>#include<malloc.h>#define MAX 100 /*最大顶点数为100*/using namespace std;typedef struct NODE{ /*边表结点*/int v_num;  /*邻接点域*/int len;    /*邻接顶点与下个邻接顶点的费用*/struct NODE * next; /*指向下个邻接顶点的指针*/}EdgeNODE;/*函数声明*/void create_graph(EdgeNODE NODE[], int n, int e);int fgraph(EdgeNODE NODE[], int cost[], int route[], int path[], int n);void show_route(int route[]);int main(){int n, e;   /*顶点数n，边数e*/cout << "请输入图的顶点数和边数:";cin >> n >> e; EdgeNODE * NODE = new EdgeNODE[n]; //多段图邻接表头节点int * cost = new int[n];           //在阶段决策中，各个顶点到收点的最小费用int * route = new int[n];          //从源点到收点的最短路径上的顶点编号int * path = new int[n];/*在阶段决策中，各个顶点到收点的最短路径上的前方顶点编号*/create_graph(NODE, n, e);      //创建图的邻接表cout << endl<<"顶点到收点的最小花费为：";cout<<fgraph(NODE, cost, route, path, n); //输出最短路径费用cout <<endl<< "路径为：";show_route(route);  //输出最短路径system("pause");return 0;}/*创建图的邻接表*/void create_graph(EdgeNODE NODE[], int n, int e){EdgeNODE * p;for (int k = 0; k< n; k++){NODE[k].v_num = k;NODE[k].len = 0;NODE[k].next = NULL;}cout <<endl<< "请输入"<<e<<"条边<i,j>和路径长度w：\n";int i, j, w; //i为边起点，j为边终点，w为边权值for (int t = 0; t < e; t++){cin >> i >> j >> w;  //输入边首尾点编号及其权值p = (EdgeNODE *)malloc(sizeof(EdgeNODE));p->v_num = j;p->len = w;p->next = NODE[i].next;NODE[i].next = p;}}/*求最短路径费用*/int fgraph(EdgeNODE NODE[], int cost[], int route[], int path[], int n){EdgeNODE * pnode;// 初始化for (int i = 0; i < n; i++){   cost[i] = MAX;route[i] = 0;path[i] = -1;}cost[n - 1] = 0;for (int i = n - 2; i >= 0; i--){/*计算各个顶点到收点的最短费用，并确定各个顶点到收点的最小花费路径的前方顶点*/pnode = NODE[i].next;while (pnode != NULL){if (pnode->len + cost[pnode->v_num] < cost[i]){cost[i] = pnode->len + cost[pnode->v_num];path[i] = pnode->v_num;}pnode = pnode->next;}}/*从源点开始，递推的确定其前方顶点，直到收点为止*/int j = 0;  //源点为0while ((route[j] != n - 1) && (path[j] != -1)){j++;route[j] = path[route[j-1]];}return cost[0];}/*打印最短路径*/void show_route(int route[]){cout << route[0];for (int i = 1; route[i] != NULL;i++)cout << "-->" << route[i];cout << endl;}
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