最短路径(单源dijkstra_bfs邻接表形式).txt

ACM资料大集合

//单源最短路径,用于路权相等的情况,dijkstra优化为bfs,邻接表形式,复杂度O(m)
//求出源s到所有点的最短路经,传入图的大小n和邻接表list,边权值len
//返回到各点最短距离min[]和路径pre[],pre[i]记录s到i路径上i的父结点,pre[s]=-1
//可更改路权类型,但必须非负且相等!
#define MAXN 200
#define inf 1000000000
typedef int elem_t;
struct edge_t{
	int from,to;
	edge_t* next;
};

void dijkstra(int n,edge_t* list[],elem_t len,int s,elem_t* min,int* pre){
	edge_t* t;
	int i,que[MAXN],f=0,r=0,p=1,l=1;
	for (i=0;i<n;i++)
		min[i]=inf;
	min[que[0]=s]=0,pre[s]=-1;
	for (;r<=f;l++,r=f+1,f=p-1)
		for (i=r;i<=f;i++)
			for (t=list[que[i]];t;t=t->next)
				if (min[t->to]==inf)
					min[que[p++]=t->to]=len*l,pre[t->to]=que[i];
}