Adds BST with insert

src/main/java/net/abhinavsarkar/algorist/BinarySearchTree.java

@@ -1,5 +1,96 @@
 package net.abhinavsarkar.algorist;
 
-public class BinarySearchTree
+public class BinarySearchTree<K extends Comparable<K>,V>
 {
+
+    private Node<K,V> root;
+
+    public BinarySearchTree() {
+        this.root = null;
+    }
+
+    public void insert(K key, V val) {
+        if (this.root == null) {
+            this.root = new Node<>(key, val);
+        } else {
+            this.root.insert(key, val);
+        }
+    }
+
+    public String toString() {
+        return this.root.toString(0).toString();
+    }
+
+    public static class Node<K extends Comparable<K>,V> {
+        private K key;
+        private V val;
+        private Node<K,V> left;
+        private Node<K,V> right;
+
+        public Node(K key, V val) {
+            this.key = key;
+            this.val = val;
+        }
+        public V getVal()
+        {
+            return val;
+        }
+        public K getKey()
+        {
+            return key;
+        }
+
+        public void insert(K key, V val)
+        {
+            if (this.key == key) {
+                this.val = val;
+            } else if (this.key.compareTo(key) > 0) {
+                if (this.left == null) {
+                    this.left = new Node<>(key, val);
+                } else {
+                    this.left.insert(key, val);
+                }
+            } else {
+                if (this.right == null) {
+                    this.right = new Node<>(key, val);
+                } else {
+                    this.right.insert(key, val);
+                }
+            }
+        }
+
+        public StringBuilder toString(int level) {
+            StringBuilder sb = new StringBuilder()
+                    .append(gutter(level))
+                    .append("<" + key + ":" + val + ">\n");
+            if (this.left != null) {
+                sb.append(this.left.toString(level + 1));
+            }
+            if (this.right != null) {
+                sb.append(this.right.toString(level + 1));
+            }
+            return sb;
+        }
+
+        private static StringBuilder gutter(int times) {
+            StringBuilder sb = new StringBuilder();
+            for (int i = 0; i < times; i++)
+            {
+                sb.append(' ');
+            }
+            return sb.append("|— ");
+        }
+    }
+
+    public static void main(String[] args)
+    {
+        BinarySearchTree<String, String> bst = new BinarySearchTree<>();
+        bst.insert("b", "barista");
+        bst.insert("a", "abhinav");
+        bst.insert("c", "carpool");
+        bst.insert("d", "carl");
+
+        System.out.println(bst);
+    }
+
 }