連結串列

#include <map>  
#include <cmath>  
#include <queue>  
#include <cstdio>  
#include <string>  
#include <cstring>  
#include <iostream>  
#include <algorithm> 
#include <sstream> 
#include <time.h> 
#include <vector>
#include <list>
#include <stack>
using namespace std;
struct ListNode {
	int val;
	ListNode *next;
	ListNode(int x) : val(x), next(NULL) {}
};

//建立一個具有n個節點的連結串列，從鍵盤輸入資料將其初始化，並返回連結串列的首節點指標
ListNode *createNode(int n)
{
	ListNode *pHead(0), //首節點指標 
		*pRear(0), //尾節點指標
		*pNew; //新節點指標
	int i;
	for (i = 0; i<n; i++)
	{
		pNew = new ListNode(0);
		cin >> pNew->val;
		if (0 == i)
		{
			pRear = pHead = pNew;
		}
		else
		{
			pRear->next = pNew;
		}
		pNew->next = NULL;
		pRear = pNew;
	}
	return pHead;
}

//輸出連結串列中的內容
void printNode(ListNode *pHead)
{
	ListNode *pTemp = pHead;

	while (pTemp != NULL)
	{
		cout << pTemp->val;
		pTemp = pTemp->next;
	}
	cout << endl;
}

//查詢連結串列中具有指定值的節點，並返回此節點指標
ListNode *searchNode(ListNode *pHead, int val)
{
	ListNode *pDest = pHead;
	while (pDest->next != NULL && pDest->val != val)
		pDest = pDest->next;
	if (pDest->val == val)
		return pDest;
	else
		return NULL;
}

ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {

	int a = 0, b = 0;
	int num = 0;
	ListNode *LL = l1;
	while (LL != NULL)
	{
		a += LL->val*pow(10, num);
		num++;
		LL = LL->next;
	}
	LL = l2;
	num = 0;
	while (LL != NULL)
	{
		b += LL->val*pow(10, num);
		num++;
		LL = LL->next;
	}
	int c = a + b;
	cout << c << endl;
	ListNode *out, *save(0);
	//呼叫前必須分配空間（指標賦值）
	out = new ListNode(0);		
	out->val = c % 10;
	save = out;
	while ((c /= 10))
	{
		ListNode *front;
		front = new ListNode(0);
		front->val = c % 10;
		save->next = front;
		save = front;
	}
	save->next = NULL;
	return out;
}
int main()
{
	int i, j, N, M;
	//m和n分別表示畫布的寬度和高度，q表示畫圖操作的個數
	cin >> N ;		
	ListNode *P = createNode(N);
	printNode(P);
	ListNode *q = createNode(N);
	printNode(q);
	ListNode * out = addTwoNumbers(P, q);
	printNode(out);
	cin >> N >> M;
	return 0;
}