leetcode第九十二题_反转链表2

leetcode第九十二题_反转链表2

难度：Medium
掌握程度：Low

var reverseBetween = function(head, m, n) {
#和反转列表1一样设置3个指针
    let prev = null;
    let curr = head;
    let next = head;
    for(let i = 1;i<m;i++){
        prev = curr;
        curr = curr.next;
	}
	#另外设置2个固定指针
    let prev2 = prev;
    let curr2 = curr;

    for(let i=m;i<=n;i++){
        next = curr.next;
        curr.next = prev;
        prev = curr;
        curr = next;
    }
    #这里是防止m=1,n=5的情况，也就是说是从最开头开始的
    if(prev2 !== null){
        prev2.next = prev;
    }else{
        head = prev;
    }
    curr2.next = curr;
    return head;
};