1. @interface Node : NSObject
  2. @property(nonatomic,strong)NSString *value;
  3. @property(nonatomic,strong)Node *next;

Queue的头文件内容：

  1. #import <Foundation/Foundation.h>
  2. @class Node;
  3. @interface Queue : NSObject
  4. @property  (strong,nonatomic) Node  *first;
  5. @property  (strong,nonatomic)  Node  *last;
  6. @property  (assign,nonatomic) NSInteger  count;
  7. -(BOOL)isEmpty;
  8. -(NSInteger)size;
  9. -(void)enqueue:(NSString *)value;
  10. -(NSString *)dequeue;
  11. -(void)remove:(NSString *)value;
  12. @end
  13. Queue的实现内容：
  14. #import "Queue.h"
  15. #import "Node.h"
  16. @implementation Queue
  17. -(BOOL)isEmpty{
  18.     return self.count==0;
  19. }
  20. -(NSInteger)size{
  21.     return self.count;
  22. }
  23. -(void)enqueue:(NSString *)value{
  24.     Node  *oldLast=self.last;
  25.     self.last=[[Node alloc]init];
  26.     self.last.data=value;
  27.     self.last.next=NULL;
  28.     oldLast.next=self.last;
  29.     if ([self isEmpty]) {
  30.         self.first=self.last;
  31.     }else{
  32.         oldLast.next=self.last;
  33.     }
  34.     self.count=self.count+1;
  35. }
  36. -(NSString *)dequeue{
  37.     if ([self isEmpty]) {
  38.         return [NSString stringWithFormat:@"-1"];
  39.     }
  40.     NSString  *result=self.first.data;
  41.     self.first=self.first.next;
  42.     self.count=self.count-1;
  43.     return result;
  44. }
  45. -(void)remove:(NSString *)value{
  46.     //判断是不是头部节点
  47.     if ([self.first.data isEqualToString:value]) {
  48.         self.first=self.first.next;
  49.         self.count=self.count-1;
  50.     }else
  51.     {
  52.         Node  *node=self.first;
  53.         while (node!=NULL)
  54.         {
  55.             if ([node.next.data isEqualToString:value])
  56.             {
  57.                 node.next=node.next.next;
  58.                 self.count=self.count-1;
  59.                 break;
  60.             }
  61.             node=node.next;
  62.         }
  63.     }
  64. }
  65. @end