贪心算法之拓扑排序2

#include<stdio.h>
#include<stdlib.h>
#define MAX_VEXTEX_NUM 20
#define M 20
#define STACK_INIT_SIZE 100
#define STACKINCREMENT 10
#define OK 1
#define ERROR 0
typedef int ElemType;
typedef struct ArcNode
{
int adjvex;
struct ArcNode *nextarc;
}ArcNode;
typedef struct VNode
{
int data;
ArcNode *firstarc;
}VNode,AdjList[MAX_VEXTEX_NUM];
typedef struct
{
AdjList vertices;
int vexnum, arcnum;
}ALGraph;
typedef struct //构件栈
{
ElemType *base;
ElemType *top;
int stacksize;
}SqStack;
void InitStack(SqStack *); //函数声明
int Pop(SqStack *, ElemType *);
void Push(SqStack *,ElemType );
int StackEmpty(SqStack *);
void CreatGraph(ALGraph *);
void FindInDegree(ALGraph , int * );
void TopologicalSort(ALGraph );
void InitStack(SqStack *S)//初始化栈
{
S->base=(ElemType *)malloc(STACK_INIT_SIZE*sizeof(ElemType));
if(!S->base)
{
printf("memory allocation failed, goodbye");
exit(1);
}
S->top=S->base;
S->stacksize=STACK_INIT_SIZE;
}
int Pop(SqStack *S,ElemType *e)//出栈操作
{
if(S->top==S->base)
{return ERROR;}
*e=*--S->top;
//printf("%d/n",e);
// return e;
return 0;
}
void Push(SqStack *S,ElemType e)//进栈操作
{if(S->top-S->base>=S->stacksize)
{
S->base = (ElemType *)realloc(S->base,(S->stacksize+STACKINCREMENT)*sizeof(ElemType));
if(!S->base)
{
printf("memory allocation failed, goodbye");
exit(1);
}
S->top = S->base+S->stacksize;
S->stacksize+=STACKINCREMENT;
}*S->top++=e;
}
int StackEmpty(SqStack *S)//判断栈是否为空
{
if(S->top==S->base)
return OK;
else
return ERROR;}
void CreatGraph(ALGraph *G)//构件图
{int m, n, i;
ArcNode *p;
printf("请输入顶点数和边数:");
scanf("%d%d",&G->vexnum,&G->arcnum);
for (i = 1; i <= G->vexnum; i++)
{G->vertices[i].data = i;
G->vertices[i].firstarc = NULL;
}
for (i = 1; i <= G->arcnum; i++) //输入存在边的点集合
{
printf("/n请输入存在边的两个顶点的序号:");
scanf("%d%d",&n,&m);
while (n < 0 || n > G->vexnum || m < 0 || m > G->vexnum)
{printf("输入的顶点序号不正确 请重新输入:");
scanf("%d%d",&n,&m);
}
p = (ArcNode*)malloc(sizeof(ArcNode));
if (p == NULL)
{printf("memory allocation failed,goodbey");
exit(1);
}
p->adjvex = m;
p->nextarc = G->vertices
.firstarc;
G->vertices
.firstarc = p;
}
printf("建立的邻接表为:/n"); //输出建立好的邻接表
for(i = 1; i <= G->vexnum; i++)
{
printf("%d",G->vertices[i].data);
for(p = G->vertices[i].firstarc; p; p = p->nextarc)
printf("%3d",p->adjvex);
printf("/n");
}}
void FindInDegree(ALGraph G, int indegree[])//求入度操作
{
int i;
for (i = 1; i <= G.vexnum; i++)
{
indegree[i] = 0;
}
for (i = 1; i <= G.vexnum; i++)
{while (G.vertices[i].firstarc)
{indegree[G.vertices[i].firstarc->adjvex]++;
G.vertices[i].firstarc = G.vertices[i].firstarc->nextarc;
}
}
}
void TopologicalSort(ALGraph G) //进行拓扑排序
{
int indegree[M];
int i, k, n;
int count = 0;
ArcNode *p;
SqStack S;
FindInDegree(G, indegree);
InitStack(&S);
for (i = 1; i <= G.vexnum; i++)
{
printf("第%d个点的入度为%d /n", i, indegree[i]);
}
printf("/n");
for ( i = 1; i <= G.vexnum; i++)
{
if (!indegree[i])
Push(&S,i);
}
printf("进行拓扑排序输出顺序为:"); //输出结果
while(!StackEmpty(&S))
{
Pop(&S,&n);
printf("%4d",G.vertices
.data);
count++;
for (p = G.vertices
.firstarc; p != NULL; p = p->nextarc)
{
k = p->adjvex;
if (!(--indegree[k]))
{
Push(&S,k);
}
}

}printf("/n");

if (count < G.vexnum)
{
printf("出现错误/n");
}
else
{
printf("排序成功/n");
}
}
int main(void) //主函数
{
ALGraph G;
CreatGraph(&G);
TopologicalSort(G);
system("pause");
return 0;
}