solves cousins in binary tre

Author: anishLearnsToCode

README.md

@@ -266,7 +266,7 @@
 | 977 | [Squares of a Sorted Array](https://leetcode.com/problems/squares-of-a-sorted-array) | |
 | 985 | [Sum of Even Numbers after Queries](https://leetcode.com/problems/sum-of-even-numbers-after-queries) | |
 | 989 | [Add to Array Form of Integer](https://leetcode.com/problems/add-to-array-form-of-integer) | [![Java](assets/java.png)](src/AddToArrayFormOfInteger.java) |
-| 993 | [Cousins in Binary Tree](https://leetcode.com/problems/cousins-in-binary-tree) | |
+| 993 | [Cousins in Binary Tree](https://leetcode.com/problems/cousins-in-binary-tree) | [![Java](assets/java.png)](src/CousinsInBinaryTree.java) |
 | 997 | [Find the Town Judge](https://leetcode.com/problems/find-the-town-judge) | |
 | 999 | [Available Captures for Rook](https://leetcode.com/problems/available-captures-for-rook) | |
 | 1002 | [Find Common Characters](https://leetcode.com/problems/find-common-characters) | |

src/CousinsInBinaryTree.java

@@ -0,0 +1,40 @@
+public class CousinsInBinaryTree {
+
+    public boolean isCousins(TreeNode root, int x, int y) {
+        NodeInfo X = getNodeInfo(root, x);
+        NodeInfo Y = getNodeInfo(root, y);
+        return X.depth == Y.depth && X.parent != Y.parent;
+    }
+
+    private NodeInfo getNodeInfo(TreeNode root, int val) {
+        if (root == null) return null;
+        if (root.val == val) return new NodeInfo(null, 0);
+        if (val(root.left) == val || val(root.right) == val) return new NodeInfo(root, 1);
+        NodeInfo left = getNodeInfo(root.left, val);
+        NodeInfo right = getNodeInfo(root.right, val);
+        if (left != null) {
+            left.depth++;
+            return left;
+        }
+        if (right != null) {
+            right.depth++;
+            return right;
+        }
+        return null;
+    }
+
+    private int val(TreeNode root) {
+        if (root == null) return 0;
+        return root.val;
+    }
+
+    private static class NodeInfo {
+        TreeNode parent;
+        int depth;
+
+        NodeInfo(final TreeNode parent, final int depth) {
+            this.parent = parent;
+            this.depth = depth;
+        }
+    }
+}