面试题解(六)之普天C++笔试题

题目:

   实现双向链表删除一个节点P，在节点P后插入一个节点，写出这两个函数

题解: 

1. #include <stdio.h>
3. typedef struct tmpNode{
4.     struct tmpNode *prev;
5.     struct tmpNode *next;
6.     int value;
7. }TNode;
8. TNode *root=NULL;
9. int main(void){
10.     int value;
11.     root=(TNode *)malloc(sizeof(TNode));
12.     root->next=root;
13.     root->prev=root;
14.     root->value=0;
15.     addNode();
16.     addNode();
17.     addNode();
18.     addNode();
19.     addNode();
20.     addNode();
21.     addNode();
22.     addNode();
23.     scanf("%d",&value);
24.     insertNode(value);
25.     viewNode();
26.     scanf("%d",&value);
27.     deleteNode(value);
28.     viewNode();
29.     scanf("%d",&value);
30.     deleteNode(value);
31.     viewNode();
32.     return 0;
33. }
34. void addNode(){
35.     TNode *temp;
36.     TNode *newNode;
37.     newNode=(TNode *)malloc(sizeof(TNode));
38.     newNode->prev=newNode;
39.     newNode->next=newNode;
40.     newNode->value=0;
41.     temp=root;
42.     while(temp->next!=NULL&&temp->next!=temp){
43.         temp=temp->next;
44.     }
45.     temp->next=newNode;
46.     newNode->prev=temp;
47.     newNode->value=temp->value+1;
48. }
49. void viewNode(){
50.     TNode *temp;
51.     temp=root;
52.     while(1){
53.         printf("this node addr is %p,and the value is %d/n",temp,temp->value);
54.         if(temp->next==NULL||temp->next==temp)
55.             break;  
56.         temp=temp->next;
57.     }
58. }
59. void insertNode(int value){
60.     TNode *temp;
61.     TNode *newNode;
62.     temp=root;
63.     newNode=(TNode *)malloc(sizeof(TNode));
64.     newNode->next=newNode;
65.     newNode->prev=newNode;
66.     newNode->value=value;
67.     while(temp->value<newNode->value&&temp->next!=NULL&&temp->next!=temp){
68.         temp=temp->next;
69.     }
70.     if(temp->next!=NULL&&temp->next!=temp){
71.         TNode *tmpNode=temp->next;
72.         tmpNode->prev=newNode;
73.         newNode->next=tmpNode;
74.     }
75.     newNode->prev=temp;
76.     temp->next=newNode;
77. }
78. void deleteNode(int value){
79.     TNode *temp;
80.     temp=root;
81.     while(temp->value!=value&&temp->next!=NULL&&temp->next!=temp){
82.         temp=temp->next;
83.     }
84.     if(temp->value!=value)
85.         return;
86.     if(temp->prev!=NULL&&temp->prev!=temp){
87.         TNode *prev;
88.         prev=temp->prev;
89.         if(temp->next!=NULL&&temp->next!=temp){
90.             TNode *next;
91.             next=temp->next;
92.             prev->next=next;
93.             next->prev=prev;        
94.         }else{
95.             prev->next=prev;
96.         }
97.     }else{
98.         if(temp->next!=NULL&&temp->next!=temp){
99.             TNode *next;
100.             next=temp->next;
101.             next->prev=next;
102.             root=next;  
103.         }else{
104.             printf("can't delete root!/n");
105.             return; 
106.         }
107.     }
108.     free(temp);
109.     temp=NULL;  
110. }

编译环境: 

        gcc (GCC) 3.2.2 20030222 (Red Hat Linux 3.2.2-5)

运行过程:

[explover@Explover 20081101]$ gcc -g pl.c -o pl

pl.c:34: warning: type mismatch with previous implicit declaration

pl.c:15: warning: previous implicit declaration of `addNode'

pl.c:34: warning: `addNode' was previously implicitly declared to return `int'

pl.c:49: warning: type mismatch with previous implicit declaration

pl.c:25: warning: previous implicit declaration of `viewNode'

pl.c:49: warning: `viewNode' was previously implicitly declared to return `int'

pl.c:59: warning: type mismatch with previous implicit declaration

pl.c:24: warning: previous implicit declaration of `insertNode'

pl.c:59: warning: `insertNode' was previously implicitly declared to return `int'

pl.c:78: warning: type mismatch with previous implicit declaration

pl.c:27: warning: previous implicit declaration of `deleteNode'

pl.c:78: warning: `deleteNode' was previously implicitly declared to return `int'

[explover@Explover20081101]$ ./pl

9

this node addr is 0x80499a8,and the value is 0

this node addr is 0x80499b8,and the value is 1

this node addr is 0x80499c8,and the value is 2

this node addr is 0x80499d8,and the value is 3

this node addr is 0x80499e8,and the value is 4

this node addr is 0x80499f8,and the value is 5

this node addr is 0x8049a08,and the value is 6

this node addr is 0x8049a18,and the value is 7

this node addr is 0x8049a28,and the value is 8

this node addr is 0x8049a38,and the value is 9

5

this node addr is 0x80499a8,and the value is 0

this node addr is 0x80499b8,and the value is 1

this node addr is 0x80499c8,and the value is 2

this node addr is 0x80499d8,and the value is 3

this node addr is 0x80499e8,and the value is 4

this node addr is 0x8049a08,and the value is 6

this node addr is 0x8049a18,and the value is 7

this node addr is 0x8049a28,and the value is 8

this node addr is 0x8049a38,and the value is 9

9

this node addr is 0x80499a8,and the value is 0

this node addr is 0x80499b8,and the value is 1

this node addr is 0x80499c8,and the value is 2

this node addr is 0x80499d8,and the value is 3

this node addr is 0x80499e8,and the value is 4

this node addr is 0x8049a08,and the value is 6

this node addr is 0x8049a18,and the value is 7

this node addr is 0x8049a28,and the value is 8

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