iOS 链表

#import <Foundation/Foundation.h>@interface ListNode : NSObject/** 添加节点 @param p 节点指针 @param value 节点值 @return 头结点, 其中头结点 value 为 0 */+ (ListNode *)addNode:(ListNode *)p andVlaue:(id)value;/** 遍历单链表 @param head 头节点 */+ (void)traveraslList:(ListNode *)head resultBlock:(void(^)(NSInteger i))block;/** 单链表逆置 @param head 头节点 */+ (void)reverseList:(ListNode *)head;/** 全链表反转 */+ (ListNode *)reverse:(ListNode *)node;@end

#import "ListNode.h"@interface ListNode(){    id val;    ListNode *next;}@end@implementation ListNode+ (ListNode *)addNode:(ListNode *)p andVlaue:(id)value{    if (p == nil) {        p = [[ListNode alloc]init];        p->val = value;        p->next = nil;    }else{        p->next = [ListNode addNode:p->next andVlaue:value];    }        return p;}+ (void)traveraslList:(ListNode *)head resultBlock:(void (^)(NSInteger))block{    if (head->next == nil) {        if (block) {            block([head->val integerValue]);        }        return;    }    if (block) {        block([head->val integerValue]);    }    [ListNode traveraslList:head->next resultBlock:block];}+ (void)reverseList:(ListNode *)head{    ListNode *p = head;    ListNode *s = p->next;        while (s->next != nil) {        ListNode *t = s->next;        s->next = p;        p = s;        s = t;    }    s->next = p;    head->next->next = nil; //尾指针置为空    head->next = s; //赋值到头指针最后一位}+ (ListNode *)reverse:(ListNode *)node{    ListNode *current,*pnext,*prev;    if (!node) return nil;    if (!node->next) return node;    current = node;    pnext = current->next;    current->next = nil;    while (pnext) {        prev = pnext->next;        pnext->next = current;        pnext = prev;    }    node =  current;        return node;}@end