Java笔试题-链表

最新推荐文章于 2022-11-09 10:36:26 发布

原创最新推荐文章于 2022-11-09 10:36:26 发布 · 283 阅读

0 ·

CC 4.0 BY-SA版权

后端 #Java 专栏收录该内容

1 篇文章

订阅专栏

链表反序

/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode ReverseList(ListNode head) {
        if(head == null) {
            return null;
        }
        ListNode pre = null;
        ListNode next = null;
        while(head != null) {
            next = head.next;
            head.next = pre;
            pre = head;
            head = next;
        }
        return pre;
    }
}

合并两个有序链表

/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode Merge(ListNode list1,ListNode list2) {
        if(list1 == null || list2 == null) {
            return list1 != null ? list1 : list2;
        }
        ListNode head = null;
        if(list1.val > list2.val) {
            head = list2;
            head.next = Merge(list1, list2.next);
        } else {
            head = list1;
            head.next = Merge(list1.next, list2);
        }
        return head;
    }
}

求链表的倒数第k个结点。

/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode FindKthToTail(ListNode head,int k) {
        if(head == null || k <= 0) {
            return null;
        }
        ListNode fast = head;
        ListNode slow = head;
        for(int i = 0; i < k-1; i++) {
            if(fast.next == null) {
                return null;
            }
            fast = fast.next; 
        } 
        while(fast.next != null) {
            fast = fast.next;
            slow = slow.next;
        }
        return slow;
    }
}