graph-Dijkstra's shortest-path alogorithm

直接贴代码吧，简明易懂。

后面自己写了测试，输入数据为：

a
b
c
d
e
0 1 4
0 2 2
1 2 3
1 3 2
1 4 3
2 1 1
2 3 4
2 4 5
4 3 1

也就是课本上111的图4.9（上面为原图，下面为结果）

程序的输出结果为：

#include <iostream>
#include <string>
using namespace std;  

const int maxVertexNum = 20;
const int INF = 99999;

typedef struct dGraph{
	// vertexes
	string vertex[maxVertexNum];
	// edges
	int edges[maxVertexNum][maxVertexNum];
	int vertexNum;
	int edgeNum;
	// construct a graph
	void set(int n, int e) {
		vertexNum = n;
		edgeNum = e;
		//cout << "input vertex" << endl;
		for (int i = 0; i < n; i++)
	        cin >> vertex[i];
	    for (int i = 0; i < n; i++)
		    for (int j = 0; j < n ; j++)
		        edges[i][j] = INF;
		//cout << "input edge" << endl;
	    int weight;
	    for (int m = 0; m < e; m++) {
	    	int i,j;
	    	cin >> i >> j >> weight;
			edges[i][j] = weight;
		}
	}
	// Dijkstra's shortest-path alogorithm
	void shortestPathDj(int v) {
		bool visited[vertexNum] = {false};
		int dist[vertexNum] = {INF};
		string path[2 * vertexNum];

		// initiation
		for (int i = 0; i < vertexNum; i++) {
			dist[i] = edges[v][i];
			if (dist[i] < INF)
			    path[i] = vertex[v]+vertex[i];
			else
			    path[i] = "";
		}
		dist[v] = 0;
		visited[v] = 1;
		//
		int min;
		int i, j, k;
		for (j = 1; j < vertexNum; j++) {
			min = INF;
			// find shortest edge.
			for (i = 0; i < vertexNum; i++) {
				if (dist[i] < min && visited[i] == false) {
					min = dist[i];
					k = i;
				}
			}
			visited[k] = true;
			cout<<path[k]<<" "<<dist[k]<<endl;
			for (i = 0; i < vertexNum; i++) {
				if (dist[i] > dist[k] + edges[k][i] && visited[i] == false) {
					dist[i] = dist[k] + edges[k][i];
					path[i] = path[k] + vertex[i];
				}
			}
		}
	}

} dGraph;

int main() {
	freopen("in.txt", "r", stdin);
	dGraph G;
	G.set(5,9);
	G.shortestPathDj(0);
	return 0;
}