【数据结构】单链表习题

头文件：“test.h” 

typedef int Elem_type;

typedef struct Node
{
	Elem_type mdata;
	struct Node* pnext;
}Node, *Link;

void Init(Link phead);
Node BuyNode(Elem_type val);
//static Link BuyNode();
bool InsertTail(Link phead,Elem_type val);
void print(Link phead,Elem_type val);
Node* Search(Link phead, Elem_type val);

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

#include "test.h"

void Init(Link phead)
{
	assert(phead != NULL);
	if(phead == NULL)
	{
		return ;
	}
	phead->pnext = NULL;
}

Link BuyNode()
{
	struct Node* pnewnode = (struct Node*)malloc(sizeof(struct Node));
	assert(pnewnode != NULL);
	pnewnode->pnext = NULL;

	return pnewnode;
}

bool InsertTail(Link phead,Elem_type val)
{
	if(phead == NULL)
	{
		return false;
	}
	struct Node* pCur = phead;
	
	while(pCur->pnext != NULL)
	{
		pCur = pCur->pnext;
	}
	
	struct Node* pnewnode = BuyNode();
	pnewnode->mdata = val;
	pCur->pnext = pnewnode;
	
	return true;
}

Node* Search(Link phead, Elem_type val)
{
	if(phead == NULL)
	{
		return 0;
	}
	Node* pCur = phead->pnext;
	Node* pNext = pCur;
	while(pCur != NULL)
	{
		if(pCur->mdata == val)
		{
			return pCur;
		}
		pCur = pCur->pnext;
	}
}

void Print(Link phead)
{
	if(phead == NULL)
	{
		return ;
	}
	struct Node* pCur = phead->pnext;
	while(pCur != NULL)
	{
		printf("%3d",pCur->mdata);
		pCur = pCur->pnext;
	}
	printf("\n");
}

Node* find_k(Link phead,int k)    //第一题
{
	Node* pfast = phead->pnext;
	Node* pslow = pfast;
	int i;
	for(i = 0;i < k-1;i++)
	{
		pfast = pfast->pnext;
	}
	while(pfast->pnext != NULL)
	{
		pfast = pfast->pnext;
		pslow = pslow->pnext;
	}
	return pslow;
}

void Delete_k(Node* pCur)    //第二题
{
	Node* pNext = pCur->pnext;
	pCur->mdata = pNext->mdata;
	pCur->pnext = pNext->pnext;
	free(pNext);
	
}

int InsertFront(Node* pCur,Elem_type val)    //第三题
{
	Node* pnewnode = (Node *)malloc(sizeof(Node));
	if(pnewnode == NULL)
	{
		return 0;
	}
	pCur->pnext = pnewnode->pnext;
	pCur->pnext = pnewnode;
	pnewnode->mdata = pCur->mdata;
	pCur->mdata = val;   //注意赋值顺序
	return 1;

}

Node* Middlenode(Link phead)    //第五题
{
	if(phead == NULL)
	{
		return 0;
	}
	Node* pfast = phead;
	Node* pslow = pfast;
	while(pfast != NULL && pfast->pnext != NULL)
	{
		pfast = pfast->pnext->pnext;  //快指针是慢指针的2倍
	    pslow = pslow->pnext;
	}
	return pslow;
}

Node* Intersect(Link phead1,Link phead2)    //第四题
{
	Node* pCur1 = phead1;
	Node* pCur2 = phead2;
	int lens1 = 0;
	int lens2 = 0;

	while(pCur1->pnext != NULL)
	{
		lens1++;
		pCur1 = pCur1->pnext; 
	}
	while(pCur2->pnext != NULL)
	{
		lens2++;
		pCur2 = pCur2->pnext; 
	}

	if(pCur1 == pCur2)  //两条链表最后地址相同，说明链表相交
	{                   //以下为求交点
		int k = abs(lens1-lens2);
		pCur1 = abs(lens1-lens2)>0 ? phead1:phead2;
		pCur2 = abs(lens1-lens2)<=0 ? phead1:phead2;
		for(int i = 0;i < k;i++)
		{
			pCur1 = pCur1->pnext;
		}
		while(pCur1 != NULL)
		{
			if(pCur1 == pCur2)
			{
				return pCur1;
			}
			pCur1 = pCur1->pnext;
			pCur2 = pCur2->pnext;
		}
	}
	return NULL;
}

void PrintReverse(Link phead)   //第六题
{
	if(phead->pnext == NULL)
	{
		return ;
	}
	PrintReverse(phead->pnext);    //递归调用
	printf("%3d",phead->pnext->mdata);
}

int main()
{
	Node head;
	Init(&head);
	for(int i = 0;i < 9;i++)
	{
		InsertTail(&head,i+1);
	}
	Print(&head);
	Node* prt1 = find_k(&head,3);
	printf("prt1 Address:%x data:%d\n",prt1,prt1->mdata);

//	Node* prt2 = Search(&head,7);
//	printf("prt2 Address:%x data:%d\n",prt2,prt2->mdata);
//测试search函数

	//Node* prt3 = Search(&head,3);
	//printf("prt3 Address:%x data:%d\n",prt3,prt3->mdata);
	//if(prt3 != NULL)
	//{
	//	Delete_k(prt3);
	//}
	//Print(&head);

	//Node* prt4 = Search(&head,3);
	//printf("prt4 Address:%x data:%d\n",prt4,prt4->mdata);
	//if(prt4 != NULL)
	//{
	//	InsertFront(prt4,0);
	//}
	//Print(&head);

	//Node* prt5 = Middlenode(&head);
	//printf("prt5 Address:%x data:%d\n",prt5,prt5->mdata);

	//Node head2;
	//Init(&head2);
	//for(int i = 2;i<9;i++)
	//{
	//	InsertTail(&head2,i);
	//}
	//Print(&head2);
	//Node* prt6 = Intersect(&head,&head2);
	//if(prt6 != NULL)
	//{
	//	printf("prt6 Address:%x data:%d\n",prt6,prt6->mdata);
	//}


//	PrintReverse(&head);

	return 0;
}