[算法] 堆栈
顺序存储实现：
1 #include<stdio.h> 2 #include<stdlib.h> 3 4 typedef int Position; 5 typedef int ElementType; 6 typedef struct SNode *PtrToSNode; 7 struct SNode { 8 ElementType *Data; 9 Position Top; 10 int MaxSize; 11 }; 12 typedef PtrToSNode Stack; 13 //创建 14 Stack CreateStack(int MaxSize) { 15 Stack S=(Stack)malloc(sizeof(struct SNode)); 16 S->Data=(ElementType*)malloc(MaxSize * sizeof(ElementType)); 17 S->Top=-1; 18 S->MaxSize=MaxSize; 19 return S; 20 } 21 //入栈 22 bool IsFull(Stack S) { 23 return(S->Top==S->MaxSize-1); 24 } 25 bool Push(Stack S,ElementType X) { 26 if(IsFull(S)) { 27 printf("堆栈满"); 28 return false; 29 } else { 30 S->Data[++(S->Top)]=X; 31 return true; 32 } 33 } 34 //出栈 35 bool IsEmpty(Stack S) { 36 return(S->Top==-1); 37 } 38 ElementType Pop(Stack S) { 39 if(IsEmpty(S)) { 40 printf("堆栈空"); 41 return -1; 42 } else 43 return(S->Data[(S->Top)--]); 44 } 45 46 int main(){ 47 Stack st; 48 st = CreateStack(3); 49 Push(st,10); 50 Push(st,20); 51 Push(st,30); 52 printf("%d",Pop(st)); 53 printf("%d",Pop(st)); 54 printf("%d",Pop(st)); 55 }
分析：
1、定义结构体：数组Data[MaxSize]存储数据；Top记录栈顶元素下标；MaxSize记录堆栈容量
2、创建：为栈申请内存；根据容量为数据申请内存；初始化Top
3、入栈、出栈：都在栈顶完成；入栈判满，出栈判空；入栈先加，出栈后减
链式存储实现：
1 #include<stdio.h> 2 #include<stdlib.h> 3 typedef int ElementType; 4 typedef struct SNode *PtrToSNode; 5 struct SNode { 6 ElementType Data; 7 PtrToSNode Next; 8 }; 9 typedef PtrToSNode Stack; 10 //创建 11 Stack CreateStack() { 12 Stack S; 13 S=(Stack)malloc(sizeof(struct SNode)); 14 S->Next=NULL; 15 return S; 16 } 17 18 bool IsEmpty(Stack S) { 19 return(S->Next==NULL); 20 } 21 //压栈 22 bool Push(Stack S,ElementType X){ 23 PtrToSNode TmpCell; 24 TmpCell=(PtrToSNode)malloc(sizeof(struct SNode)); 25 TmpCell->Data=X; 26 TmpCell->Next=S->Next; 27 S->Next=TmpCell; 28 return true; 29 } 30 //出栈 31 ElementType Pop(Stack S){ 32 PtrToSNode FirstCell; 33 ElementType TopElem; 34 if(IsEmpty(S)){ 35 printf("堆栈空"); 36 return -1; 37 } 38 else{ 39 FirstCell=S->Next; 40 TopElem=FirstCell->Data; 41 S->Next=FirstCell->Next; 42 free(FirstCell); 43 return TopElem; 44 } 45 } 46 47 int main() { 48 Stack st; 49 st = CreateStack(); 50 Push(st,10); 51 Push(st,20); 52 Push(st,30); 53 printf("%d",Pop(st)); 54 printf("%d",Pop(st)); 55 printf("%d",Pop(st)); 56 }
