OC_链表实现队列

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