剑指Offer13 链表倒数第K个结点

/*************************************************************************
    > File Name: 13_KthNodeToTail.cpp
    > Author: Juntaran
    > Mail: JuntaranMail@gmail.com
    > Created Time: 2016年08月30日 星期二 15时32分25秒
 ************************************************************************/

#include <stdio.h>
#include <stdlib.h>

// 链表结构体
struct ListNode
{
    int val;
    ListNode* next;
};

// 构造链表
ListNode* createList()
{
    struct ListNode* head;
    struct ListNode* p;
    struct ListNode* q;
    head = p = (ListNode*)malloc(sizeof(ListNode));
    head->val = 0;
    
    for (int i = 1; i <= 10; ++i)
    {
        q = (ListNode*)malloc(sizeof(ListNode));
        q->val = i;
        p->next = q;
        p = q;
    }
    p->next = NULL;
    return head;
}

// 顺序输出链表
void PrintList(ListNode* head)
{
    if (head == NULL)
        return;
    ListNode* temp = head;
    printf("PrintList:
");
    while (temp != NULL)
    {
        printf("%d ", temp->val);
        temp = temp->next;
    }
    printf("
");
}

ListNode* FintKthNodeToTail(ListNode* head, int k)
{
    if (head==NULL || k<=0)
        return NULL;
    
    ListNode* fast = head;
    ListNode* slow = head;
    
    for (int i = 0; i < k - 1; ++i)
    {
        fast = fast->next;
        if (fast == NULL)
        {
            printf("Overflow!
");
            return NULL;
        }
    }
    
    while (fast->next != NULL)
    {
        slow = slow->next;
        fast = fast->next;
    }
    printf("Find: %d
", slow->val);
    
    return slow;
}

int main()
{
    ListNode* test = createList();
    PrintList(test);
    
    int k = 3;
    ListNode* find = FintKthNodeToTail(test, k);
    
    return 0;
}