Examples with ListNode com.fishercoder.common.classes.ListNode used on opensource projects

Example 6 with ListNode

use of com.fishercoder.common.classes.ListNode in project Leetcode by fishercoder1534.

the class _25 method reverseKGroup.

/**
 *We use recursion to go all the way until the end: when the number of nodes are smaller than k;
 * then we start to reverse each group of k nodes from the end towards the start.
 */
public ListNode reverseKGroup(ListNode head, int k) {
    ListNode curr = head;
    int count = 0;
    while (curr != null && count != k) {
        // find the k+1 node
        curr = curr.next;
        count++;
    }
    if (count == k) {
        /**
         *after this below recursive call finishes, it'll return head;
         * then this returned "head" will become "curr", while the head
         * in its previous callstack is the real head after this call.
         * Setting up a break point will make all of this crystal clear.
         */
        curr = reverseKGroup(curr, k);
        while (count-- > 0) {
            ListNode temp = head.next;
            head.next = curr;
            curr = head;
            head = temp;
        }
        head = curr;
    }
    // we run out of nodes before we hit count == k, so we'll just directly return head in this case as well
    return head;
}

Example 7 with ListNode

use of com.fishercoder.common.classes.ListNode in project Leetcode by fishercoder1534.

the class _445 method popIntoStack.

private Deque<Integer> popIntoStack(ListNode head) {
    ListNode tmp = head;
    Deque<Integer> stack = new ArrayDeque<>();
    while (tmp != null) {
        stack.push(tmp.val);
        tmp = tmp.next;
    }
    return stack;
}

Example 8 with ListNode

use of com.fishercoder.common.classes.ListNode in project Leetcode by fishercoder1534.

the class CommonUtils method reverseList.

/**
 * If you want to print the reversed list out, you need to return the reversed list's head,
 * which was the end node of the original node. using the following function.
 */
public static ListNode reverseList(ListNode head) {
    if (head == null || head.next == null) {
        return head;
    }
    ListNode previous;
    ListNode current;
    ListNode next;
    previous = head;
    current = head.next;
    while (current != null) {
        next = current.next;
        current.next = previous;
        previous = current;
        current = next;
    }
    head.next = null;
    return previous;
}

Example 9 with ListNode

use of com.fishercoder.common.classes.ListNode in project Leetcode by fishercoder1534.

the class CommonUtils method printList.

public static void printList(final ListNode head) {
    ListNode temp = head;
    System.out.println("--------------------------------------------");
    while (temp != null) {
        System.out.print(temp.val);
        temp = temp.next;
        if (temp != null) {
            System.out.print("->");
        }
    }
    System.out.println();
}

Example 10 with ListNode

use of com.fishercoder.common.classes.ListNode in project Leetcode by fishercoder1534.

the class _142 method detectCycle.

public ListNode detectCycle(ListNode head) {
    ListNode slow = head;
    ListNode fast = head;
    while (fast != null && fast.next != null) {
        slow = slow.next;
        fast = fast.next.next;
        if (slow == fast) {
            ListNode slow2 = head;
            while (slow2 != slow) {
                slow = slow.next;
                slow2 = slow2.next;
            }
            return slow;
        }
    }
    return null;
}