面试题之陈利人 单链表和之恋

单链表和之恋

• 真言

年轻人多听听音乐---周杰伦。给大家推荐一首歌 《单身礼物》，歌手赵凯。

• 引言

题目已经过去很久，但是我不能放过自己，必须补上。我把自己的电脑屏幕调成黑白的啦，博客也只能看成黑白的啦。建议大家也调成黑白的，保护眼睛。

• 题目

• 思路

举个例子说吧，不知你们喜不喜欢图，我很喜欢，形象生动。。。。

• 实验

• 代码

test.cpp

#include<iostream>
using namespace std;

// declare size for list
int const size = 30;

// define class for list
class node
{
public:
	int d;
	node * next;
	node()
	{
		d = 0 ;
		next = NULL ;
	}
};

// function declare for add list
node * Add(node * La,node* Lb);

int main()
{
	// list for a and b without head node
	node *L_a = NULL ,*pa;
	node *L_b = NULL ,*pb;
	node * R = NULL ,*pr;
	for(int i= 0;i<size;i++ )
	{
		pa = new node;
		pb = new node;

		pa->d = rand() % 10;
		pb->d = rand() % 10;

		pa->next = L_a;
		L_a  = pa;

		pb->next = L_b;
		L_b = pb ;
	}


	cout<<"La="<<endl;
	pa = L_a;
	while (pa)
	{
		cout<<pa->d<<" "; 
		pa = pa->next ;
	}
	cout<<endl;

	cout<<"Lb="<<endl;
	pb = L_b;
	while(pb)
	{
		cout<<pb->d<<" "; 
		pb = pb->next;
	}
	cout<<endl;

	R = Add(L_a,L_b);

	cout<<"result="<<endl;
	pr = R;
	while(pr)
	{
		cout<<pr->d<<" ";
		pr =pr->next;
	}
	cout<<endl;


	system("pause");
	return 0;
}


// function define for add list
node * Add(node * La,node* Lb)
{
	if(La == NULL)
		return Lb;
	else if(Lb == NULL)
		return NULL;
	node * result = NULL;
	node *pa = La,*pb = Lb,*pr;

	while(pa && pb)
	{
		if((pa->d)<0 || (pa->d)>9 || (pb->d)<0 || (pb->d)>9)
		{
			cout<<"exception of input add for list elem"<<endl;
			return NULL;
		}
		pr = new node ;
		pr->d = pa->d + pb->d;
		pr->next = result;
		result = pr;
		pa = pa->next;
		pb = pb->next;
	}
	pr = result;
	while(pr && pr->next)
	{
		pr->next->d += (pr->d)/10 ;
		pr->d = (pr->d) %10;
		pr = pr->next;
	}

	// the max bit go forward
	if((pr->d) >= 10)
	{
		node * max = new node;
		max->d  = (pr->d) / 10;
		pr->d = (pr->d) % 10;
		max->next = NULL;
		pr->next = max ;
	}

	// reverse the list result
	pr = result ;
	node * pnext = NULL ;
	while(pr && pr->next)
	{
		pnext = pr->next;
		pr -> next = pr->next->next;
		pnext -> next = result;
		result = pnext;		
	}

	while(result)
	{
		if(result->d == 0)
			result = result->next;
		else break;
	}
	return result;
}