【leetcode】【单链表】【160】Intersection of Two Linked Lists

#include<iostream>
using namespace std;

struct ListNode {
	int val;
	ListNode *next;
	ListNode(int x) : val(x), next(NULL) {}
};

class Solution {
public:
	ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
		if (headA == NULL || headB == NULL)
			return NULL;

		int numOfNodeA = 0; //链表A的长度
		int numOfNodeB = 0;//链表B的长度
		ListNode* curA = headA;
		ListNode* curB = headB;
		while (curA){
			++numOfNodeA;
			curA = curA->next;
		}
		while (curB){
			++numOfNodeB;
			curB = curB->next;
		}
		int num = numOfNodeA - numOfNodeB;//两链表长度差
		curA = headA;
		curB = headB;
		if (num > 0){ //链表A比B长
			while (num-- > 0)
				curA = curA->next;
		}else{//链表A不比B长
			num = -num;
			while (num-- > 0)
				curB = curB->next;
		}
		while (curA&&curB){
			if (curA == curB)
				return curA;
			else{
				curA = curA->next;
				curB = curB->next;
			}
		}
		return NULL;
	}
	ListNode* createList(ListNode* head){
		int numOfNode;
		int value;
		cout << "please input number of listNode:";
		cin >> numOfNode;
		cin >> value;
		head = new ListNode(value);
		ListNode* cur = head;
		for (int i = 1; i < numOfNode; ++i){
			cin >> value;
			ListNode* temp = new ListNode(value);
			cur->next = temp;
			cur = temp;
		}
		//cur->next = head;
		return head;
	}
	void printNode(ListNode* head){
		ListNode* cur = head;
		while (cur){
			cout << cur->val << " ";
			cur = cur->next;
		}
		cout << endl;
	}
};

int main(){
	ListNode* headA = NULL;
	ListNode* headB = NULL;
	Solution solution;
	headA = solution.createList(headA);
	solution.printNode(headA);

	headB = solution.createList(headB);
	solution.printNode(headB);

	ListNode* begin = solution.getIntersectionNode(headA, headB);

	cout << (begin==NULL?0:begin->val) << endl;

	system("pause");
	return 0;
}