android-notes/blogs/Algorithm/剑指 Offer/链表相关.md

链表相关

06: 从头到尾打印链表

class Solution {
    public int[] reversePrint(ListNode head) {
        ListNode temp = head;
        int size = 0;
        while (temp != null) {
            temp = temp.next;
            size++;
        }
        int[] result = new int[size];
        int index = size - 1;
        while (head != null) {
            result[index--] = head.val;
            head = head.next;
        }
        return result;
    }
}

class Solution {
    public int[] reversePrint(ListNode head) {
        Stack<ListNode> stack = new Stack<ListNode>();
        ListNode temp = head;
        while (temp != null) {
            stack.push(temp);
            temp = temp.next;
        }
        int size = stack.size();
        int[] print = new int[size];
        for (int i = 0; i < size; i++) {
            print[i] = stack.pop().val;
        }
        return print;
    }
}

22:链表中倒数第 k 个节点

class Solution {
    public ListNode getKthFromEnd(ListNode head, int k) {
        int length = 0;
        ListNode temp = head;
        while (temp != null) {
            temp = temp.next;
            length++;
        }
        for (int i = 0; i < length - k; i++) {
            head = head.next;
        }
        return head;
    }
}

class Solution {
    public ListNode getKthFromEnd(ListNode head, int k) {
        ListNode h0 = head;
        for (int i = 0; i < k; i++) {
            h0 = h0.next;
        }
        while (h0 != null) {
            h0 = h0.next;
            head = head.next;
        }
        return head;
    }
}