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AOV网络拓扑排序

2014-03-23 10:37 309 查看
这个算法,主要是为输出一个无环图的拓扑序列

算法思想:

主要依赖一个栈,用来存放没有入度的节点,每次读取栈顶元素,并将栈顶元素的后继节点入度减一,如果再次出现入度为零的节点,就加入到栈中。参考《大话数据结构》,写下下面完整代码,并发现,其中程序的进行,出现错误。v6执行完,应该执行v9,因为此时v9是站顶元素,并不是v0.

算法流程:

int topGraph(graph g){
EdgeNode *e;
int i,k,gettop;
int top = 0 ;
int count = 0;
int *stack;
stack = (int *)malloc(g->numVertexes * sizeof(int));
for(i=0;i<g->numVertexes;i++){
if(g->headlist[i].in == 0) //把入度为0的,即没有入度的点入栈
stack[++top] = i;
}
while(top){
gettop = stack[top--];
printf("%d ",gettop);
count++;
for(e = g->headlist[gettop].fnode; e ; e=e->next){ //一次遍历链表,减少各个子节点的入度
k = e->data;
if(!(--g->headlist[k].in))
stack[++top] = k;
}
}
if(count < g->numVertexes)
return ERROR;
else
return OK;
}


全部代码:

#include <stdio.h>
#include <stdlib.h>
#define MAX 14
#define ERROR 1
#define OK 0
typedef struct edgeNode{
int data;
struct edgeNode *next;
}EdgeNode;
typedef struct headNode{
int in;
int data;
EdgeNode *fnode;
}HeadNode,HeadList[MAX];
typedef struct{
HeadList headlist;
int numEdges,numVertexes;
}Graph,*graph;

void initGraph(graph g);
int inputInfo(graph g,int tar,int in,int data,int first);
void printGraph(graph g);
int topGraph(graph g);
int main(){
Graph *g = (Graph *)malloc(sizeof(Graph));
initGraph(g);
printGraph(g);

if(topGraph(g) == ERROR)
printf("有环路!\n");
else
printf("没有环路!\n");

free(g);
getchar();
return 0;
}
int topGraph(graph g){ EdgeNode *e; int i,k,gettop; int top = 0 ; int count = 0; int *stack; stack = (int *)malloc(g->numVertexes * sizeof(int)); for(i=0;i<g->numVertexes;i++){ if(g->headlist[i].in == 0) //把入度为0的,即没有入度的点入栈 stack[++top] = i; } while(top){ gettop = stack[top--]; printf("%d ",gettop); count++; for(e = g->headlist[gettop].fnode; e ; e=e->next){ //一次遍历链表,减少各个子节点的入度 k = e->data; if(!(--g->headlist[k].in)) stack[++top] = k; } } if(count < g->numVertexes) return ERROR; else return OK; }
void printGraph(graph g){
int i;
printf("vertex:%d,edges:%d\n",g->numVertexes,g->numEdges);
EdgeNode *e = (EdgeNode *)malloc(sizeof(EdgeNode));
for(i=0;i<MAX;i++){
printf("[in:%d]%d",g->headlist[i].in,g->headlist[i].data);
e = g->headlist[i].fnode;
while(e != NULL){
printf("->%d",e->data);
e = e->next;
}
printf("\n");
}
free(e);
}
void initGraph(graph g){
g->numVertexes = MAX;
g->numEdges = 0;
int i;
for(i=0;i<MAX;i++){
g->headlist[i].fnode = NULL;
}
inputInfo(g,0,0,0,4);
inputInfo(g,0,0,0,5);
inputInfo(g,0,0,0,11);

inputInfo(g,1,0,1,2);
inputInfo(g,1,0,1,4);
inputInfo(g,1,0,1,8);

inputInfo(g,2,2,2,5);
inputInfo(g,2,2,2,6);
inputInfo(g,2,2,2,9);

inputInfo(g,3,0,3,2);
inputInfo(g,3,0,3,13);

inputInfo(g,4,2,4,7);

inputInfo(g,5,3,5,8);
inputInfo(g,5,3,5,12);

inputInfo(g,6,1,6,5);

inputInfo(g,7,2,7,-1);

inputInfo(g,8,2,8,7);

inputInfo(g,9,1,9,10);
inputInfo(g,9,1,9,11);

inputInfo(g,10,1,10,13);

inputInfo(g,11,2,11,-1);

inputInfo(g,12,1,12,9);

inputInfo(g,13,2,13,-1);
}
int inputInfo(graph g,int tar,int in,int data,int first){
g->numEdges++;

if(first == -1){ //没有后继的边节点
g->headlist[tar].in = in;
g->headlist[tar].data = data;
return 1;
}

if(!g->headlist[tar].fnode){ //观察是否已经初始化
g->headlist[tar].in = in;
g->headlist[tar].data = data;
}
EdgeNode *e = (EdgeNode *)malloc(sizeof(EdgeNode));
e->data = first;
e->next = g->headlist[tar].fnode;
g->headlist[tar].fnode = e;
return 0;
}


执行示例:

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