leetcode 92. 反轉連結清單 II (JavaScript實作)
- 問題描述
- 代碼
問題描述
反轉從位置 m 到 n 的連結清單。請使用一趟掃描完成反轉。
說明:
1 ≤ m ≤ n ≤ 連結清單長度
示例:
輸入: 1->2->3->4->5->NULL, m = 2, n = 4
輸出: 1->4->3->2->5->NULL
代碼
var reverseBetween = function(head, m, n) {
let pre = null ;
let curr = head ;
let next = head ;
for ( let i=1 ; i<m ; i++ ){
pre = curr ;
curr = curr.next;
}
let pre1 = pre ;
let curr1 = curr ;
for(let i=m ; i<=n ; i++ ){
next = curr.next ;
curr.next = pre ;
pre = curr ;
curr = next;
}
if ( pre1 != null ){
pre1.next = pre ;
}else{
head = pre ;
}
curr1.next = curr ;
return head;
};