19.go

package easy_collection

/**
 * 19. Remove Nth Node From End of List
 * <p>
 * Given a linked list, remove the n-th node from the end of list and return its head.
 * <p>
 * Example:
 * <p>
 * Given linked list: 1->2->3->4->5, and n = 2.
 * <p>
 * After removing the second node from the end, the linked list becomes 1->2->3->5.
 * <p>
 * Note:
 * <p>
 * Given n will always be valid.
 * <p>
 * Follow up:
 * <p>
 * Could you do this in one pass?
 */

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */

func removeNthFromEnd(head *ListNode, n int) *ListNode {
	start := &ListNode{Val: 0}
	slow := start
	fast := start
	slow.Next = head
	for i := 0; i <= n; i++ {
		fast = fast.Next
	}
	for fast != nil {
		slow = slow.Next
		fast = fast.Next
	}
	slow.Next = slow.Next.Next
	return start.Next
}