Time: 9 ms (61.28%), Space: 45.7 MB (51.63%) - LeetHub

Author: JeonJe

LeetCode/Medium/0707-design-linked-list/0707-design-linked-list.java

@@ -0,0 +1,76 @@
+class MyLinkedList {
+
+    public static class Node {
+       int value;
+        Node next;
+        public Node(int v) {
+            value = v;
+        }
+    }
+
+    private final Node head;
+    private int size;
+
+    public MyLinkedList() {
+        head = new Node(0);
+        size = 0;
+    }
+    
+    public int get(int index) {
+        if(index < 0 || index >= size) {
+            return -1;
+        }
+        Node cur = head.next;
+        for(int i = 0; i < index; i++) {
+            cur = cur.next;
+        }
+        return cur.value;
+        
+    }
+    
+    public void addAtHead(int val) {
+        addAtIndex(0, val);
+    }
+    
+    public void addAtTail(int val) {
+        addAtIndex(size, val);
+    }
+    
+    public void addAtIndex(int index, int val) {
+        if(index < 0|| index > size) {
+            return ;
+        }
+        Node prev = head;
+        for(int i = 0; i < index; i++) {
+            prev = prev.next;
+        }
+        Node n = new Node(val);
+        n.next = prev.next;
+        prev.next = n;
+        size++;
+        
+    }
+    
+    public void deleteAtIndex(int index) {
+        if(index < 0|| index >= size) {
+            return ;
+        }
+        Node prev = head;
+        for(int i = 0; i < index; i++) {
+            prev = prev.next;
+        }
+        prev.next = prev.next.next;
+        size--;
+        
+    }
+}
+
+/**
+ * Your MyLinkedList object will be instantiated and called as such:
+ * MyLinkedList obj = new MyLinkedList();
+ * int param_1 = obj.get(index);
+ * obj.addAtHead(val);
+ * obj.addAtTail(val);
+ * obj.addAtIndex(index,val);
+ * obj.deleteAtIndex(index);
+ */