/*function ListNode(x){
    this.val = x;
    this.next = null;
}*/
function FindFirstCommonNode(pHead1, pHead2)
{
    // write code here
    while(pHead1){
        if(pHead1.flag==true){
            return pHead1;
        }
        pHead1.flag=true;
        pHead1=pHead1.next;
    }
    while(pHead2){
        if(pHead2.flag==true){
            return pHead2;
        }
        pHead2.flag=true;
        pHead2=pHead2.next;
    }
    return null
}
module.exports = {
    FindFirstCommonNode : FindFirstCommonNode
};

老规矩,遍历过的节点做标记,如果遇到了遍历过的节点,那么就是入口直接返回

如果都遍历完了就为null