两种删除单链表结点的实现，一种O(n),一种O(1)

  1 //
  2 //  main.c
  3 //  SingleListDeleteNode
  4 //
  5 //  Created by xxx on 6/20/14.
  6 //  Copyright (c) 2014 xxx. All rights reserved.
  7 //
  8 
  9 #include <stdio.h>
 10 #include <stdlib.h>
 11 
 12 typedef struct Node {
 13     struct Node *next;
 14     int value;
 15 }Node;
 16 
 17 Node* genList(int *content, int length);
 18 void printList(Node *header);
 19 void releaseList(Node *header);
 20 void normalDeleteNode(Node *header, Node *node);
 21 void fashDeleteNode(Node *header, Node *node);
 22 Node* getNodeAtIndex(Node *header, int index);
 23 
 24 int main(int argc, const char * argv[])
 25 {
 26 
 27     // insert code here...
 28     printf("Hello, World!\n");
 29     
 30     Node *header = NULL;
 31     int values[10] = {1,2,3,4,5,6,7,8,9,0};
 32     header = genList(values, 10);
 33     printList(header);
 34     releaseList(header);
 35     
 36 
 37     printf("show normal delete node result!\n");
 38     header = genList(values, 10);
 39     Node *nodeToDel = getNodeAtIndex(header, 3);
 40     normalDeleteNode(header, nodeToDel);
 41     printList(header);
 42     releaseList(header);
 43 
 44     printf("show fast delete node result!\n");
 45     header = genList(values, 10);
 46     nodeToDel = getNodeAtIndex(header, 3);
 47     fashDeleteNode(header, nodeToDel);
 48     printList(header);
 49     releaseList(header);
 50     
 51     
 52     
 53     return 0;
 54 }
 55 
 56 Node* genList(int *content, int length) {
 57     Node *header = NULL;
 58     Node *curNode = NULL;
 59     for (int i=0; i<length; i++) {
 60         Node *tmp = (Node *)malloc(sizeof(Node));
 61         tmp->value = content[i];
 62         if (i == 0) {
 63             header = tmp;
 64         }
 65         if (curNode != NULL) {
 66             curNode->next = tmp;
 67         }
 68         curNode = tmp;
 69     }
 70     curNode->next = NULL;
 71     return header;
 72 }
 73 
 74 void releaseList(Node *header) {
 75     while (header != NULL) {
 76         Node *tmp = header;
 77         header = header->next;
 78         tmp->next = NULL;
 79         free(tmp);
 80         tmp = NULL;
 81     }
 82 }
 83 
 84 void printList(Node *header) {
 85     printf("LIST : ");
 86     while (header != NULL) {
 87         printf("%d",header->value);
 88         if (header->next != NULL) {
 89             printf(" -> ");
 90         }
 91         header = header->next;
 92     }
 93     printf("\n");
 94 }
 95 
 96 void normalDeleteNode(Node *header, Node *node) {
 97     while (header->next != node) {
 98         header = header->next;
 99         if (header == NULL) {
100             return;
101         }
102     }
103     header->next = header->next->next;
104     free(node);
105     node = NULL;
106 }
107 
108 void fashDeleteNode(Node *header, Node *node) {
109     if (node->next == NULL) {
110         while (header->next != node) {
111             header = header->next;
112         }
113         header->next = NULL;
114         free(node);
115         node = NULL;
116         return;
117     }
118     node->value = node->next->value;
119     Node *tmp = node->next;
120     node->next = node->next->next;
121     free(tmp);
122     tmp = NULL;
123 }
124 
125 Node* getNodeAtIndex(Node *header, int index) {
126     while (index > 0 && header != NULL) {
127         header = header->next;
128         index--;
129     }
130     return header;
131 }