题解 | 链表中环的入口结点

/*function ListNode(x){
    this.val = x;
    this.next = null;
}*/
function EntryNodeOfLoop(pHead)
{
    // write code here
    if(!pHead || !pHead.next) return null;
    let slow = pHead;
    let fast = pHead;
    while (fast && fast.next){
        slow = slow.next;
        fast = fast.next.next;
        if(slow == fast) break;
    }
    if (!fast || !fast.next) return null;
    slow = pHead;
    while(slow!= fast){
        slow = slow.next;
        fast = fast.next;
    }
    return slow;
}
module.exports = {
    EntryNodeOfLoop : EntryNodeOfLoop
};