题解 | #反转链表#

/*
 * function ListNode(x){
 *   this.val = x;
 *   this.next = null;
 * }
 */
/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 * 
 * @param head ListNode类 
 * @return ListNode类
 */
function ReverseList( head ) {
    // write code here
    let pre = null , after =null
    while(head){
        after = head.next;
        head.next = pre
        pre = head
        head = after
    }
    return pre
}
module.exports = {
    ReverseList : ReverseList
};