题解 | #链表相加(二)#

/*
struct ListNode {
    int val;
    struct ListNode *next;
    ListNode(int x) :
            val(x), next(NULL) {
    }
};*/
class Solution {
public:
    ListNode* FindFirstCommonNode( ListNode* pHead1, ListNode* pHead2) {
        ListNode*p1 =pHead1;
        ListNode*p2 =pHead2;
        int n=0,m=0;
        if(pHead1==pHead2)
        {
            return pHead1;
        }
        while(p1!=NULL)
        {
            p1=p1->next;
           n++;
        }
        while(p2!=NULL)
        {
            p2=p2->next;
           m++;
        }
        if(n>=m)
        {
            for(int i =0;i<(n-m);i++)
            {
                 pHead1=pHead1->next;
            }
        }
        else{
             for(int i =0;i<(m-n);i++)
            {
                 pHead2=pHead2->next;
            }   
        }
        for(int i = 0;i<min(m,n);i++)     
        {
             if(pHead1==pHead2)
            {
                break;
            }
            pHead1 = pHead1->next;
            pHead2 = pHead2->next;
        }
        return pHead1;
    }
};