力扣刷题记录56.1-----160. 相交链表

一、题目

二、代码

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution 
{
public:
    ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) 
    {
        int i,j;
        int length_of_a=0;
        int length_of_b=0;
        ListNode * process_node_A=headA;
        ListNode * process_node_B=headB;        
        int find_flag=0;
        while(process_node_A!=nullptr)
        {
            length_of_a++;
            process_node_A=process_node_A->next;
        }    
        while(process_node_B!=nullptr)
        {
            length_of_b++;
            process_node_B=process_node_B->next;
        }    


        if(length_of_a<length_of_b)  //保证a的长度是 长的
        {
            //getIntersectionNode(headB,headA);
           // std::cout<<"反转  "<<std::endl;
            swap(length_of_a,length_of_b);
            swap(headA,headB);
        }

        //std::cout<<" length_of_a   "<<length_of_a<<std::endl;
       // std::cout<<" length_of_b   "<<length_of_b<<std::endl;

        //处理到相同起点
        int move=length_of_a-length_of_b;
       // std::cout<<"move   "<<move<<std::endl;

        // std::cout<<"move   "<<move<<std::endl;

        for(i=1;i<=move;i++)  headA=headA->next;

        //下面的长度是相同得了
        process_node_A=headA;
        process_node_B=headB;
        while(process_node_A!=nullptr)
        {
            if(process_node_A==process_node_B) 
            { 
               // std::cout<<"结束方式1   "<<move<<std::endl; 
                return process_node_A;
                find_flag=1;
                break;
            }
            else
            {
                process_node_A=process_node_A->next;
                process_node_B=process_node_B->next;
            }
        }
         
        return nullptr;
    }
};
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三、运行结果