leetcode链接：
https://leetcode.cn/problems/remove-linked-list-elements/solution/203yi-chu-lian-biao-yuan-su-by-lewis-dxstabdzew/
方案一
暴力求解
参考： https://leetcode.cn/problems/remove-linked-list-elements/solution/yi-chu-lian-biao-yuan-su-by-leetcode-sol-654m/
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| class Solution {
public ListNode removeElements(ListNode head, int val) {
while(head != null && head.val == val) {
head = head.next;
}
if (head == null) {
return head;
}
ListNode flag = head;
while(head.next != null) {
if (head.next.val == val) {
head.next = head.next.next;
} else {
head = head.next;
}
}
return flag;
}
}
|
Accepted
- 66/66 cases passed (0 ms)
- Your runtime beats 100 % of java submissions
- Your memory usage beats 21 % of java submissions (44 MB)
分析
时间复杂度：
O( n )
空间复杂度：
O( 1 )
方案二
迭代
参考： https://leetcode.cn/problems/remove-linked-list-elements/solution/203yi-chu-lian-biao-yuan-su-by-lewis-dxstabdzew/ 中的方法三。
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| if (head == null) {
return null;
}
head.next = removeElements(head.next, val);
if (head.val == val) {
return head.next;
} else{
return head;
}
|
Accepted
- 66/66 cases passed (0 ms)
- Your runtime beats 100 % of java submissions
- Your memory usage beats 11.67 % of java submissions (44.2 MB)