Dijkstra算法

迪杰斯特拉（Dijkstra）算法求到各顶点的最短路径

#include<iostream>
#include<stdlib.h>

#define MAXINT  100000000
using namespace std;


void ShortestPath_Dijkstra(int **G, int n, int v)
{
	if ( v >= n ) return;
	bool S[n]; //标记顶点i是否求从源点到顶点的最短路径 
	int path[n]; //保存从源点v到顶点i的前驱 
	int D[n]; //保存当前各顶点到源点的最短路径长度 
	/******************初始化*********************/
	for(int i=0; i < n; i++)
	{
		S[i] = false;
		int d = *((int*) G+v*n+i );
		if ( d < MAXINT)
		{
			path[i] = v;
			D[i] = d;
		}else
		{
			D[i] = MAXINT;
			path[i] = -1;
		}
	}
	S[v] = true;
	D[v] = 0;
	/**********************初始化完成**********************/ 
	for( int i = 1; i < n; i++ )
	{
		int min = MAXINT;
		int vk;
		// 找出最短路径的一个顶点标记为true 
		for (int j = 0; j < n; j++ )
		{
			if ( !S[j] && D[j] < min )
			{
				min = D[j];
				vk = j;
			}
		}
		S[vk]  = true;
		
		//更新未求出最短路径的顶点的路径长度(新最短路径顶点被找到)
		 for (int j = 0; j < n; j++ )
		 {
		 	// <v,vk>+<vk,j> < D[j]
		 	if ( !S[j] && ( D[vk] + *((int*) G+vk*n+j )) < D[j]  ) 
		 	{
		 		D[j] = D[vk] + *((int*) G+vk*n+j ); //更新距离 
		 		path[j] = vk; //更新前驱 
			}
		 }
	}
	
	for (int i = 0; i < n; i++ )
		cout<<D[i] << " " ;
	cout<<endl;
	for (int i=0; i < n; i++ )
		cout<< path[i]<<"->"<<i<<endl;
}

int main(void) 
{
    //邻接矩阵
	int graph[6][6] = 
	{
		{ MAXINT, MAXINT, 10, MAXINT, 30, 100 },
		{ MAXINT, MAXINT, 5, MAXINT, MAXINT, MAXINT },
		{ MAXINT, MAXINT, MAXINT, 50, MAXINT, MAXINT },
		{ MAXINT, MAXINT, MAXINT, MAXINT, MAXINT, 10 },
		{ MAXINT, MAXINT, MAXINT, 20, MAXINT, 60 },
		{ MAXINT, MAXINT, MAXINT, MAXINT, MAXINT, MAXINT } 
	};
	
	ShortestPath_Dijkstra((int **)graph, 6, 0);
	
	return 0;
}