day3

Author: jlovedragon

RemoveNthNodeFromEndofList_19.java

@@ -0,0 +1,46 @@
+package com.easy;
+
+import java.util.HashMap;
+import java.util.LinkedList;
+
+/**
+ * Remove Nth Node From End of List
+ * Given a linked list, remove the nth node from the end of list and return its head.
+ *
+ * author : quantin
+ * date   : 15/7/19
+ */
+public class RemoveNthNodeFromEndofList_19 {
+	public class ListNode {
+		int val;
+		ListNode next;
+		ListNode(int x) { val = x; }
+	}
+
+	public ListNode removeNthFromEnd(ListNode head, int n) {
+		if (head == null)
+			return null;
+
+		if (head.next == null && n >= 1)
+			return null;
+
+		LinkedList<ListNode> list = new LinkedList<>();
+		ListNode p = head;
+
+		while (p != null) {
+			list.add(p);
+			p = p.next;
+		}
+
+		int len = list.size();
+
+		if (n == 1) {
+			list.get(len-2).next = null;
+		} else if (n == len) {
+			head = head.next;
+		} else {
+			list.get(list.size() - n - 1).next = list.get(list.size() - n + 1);
+		}
+		return head;
+	}
+}