Added Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree.java

varunu28 · varunu28 · commit aa1f02e76d6b · 2020-04-30T09:44:05.000-07:00
diff --git a/Medium/Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree.java b/Medium/Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree.java
@@ -0,0 +1,33 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode() {}
+ *     TreeNode(int val) { this.val = val; }
+ *     TreeNode(int val, TreeNode left, TreeNode right) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+class Solution {
+  public boolean isValidSequence(TreeNode root, int[] arr) {
+    return helper(root, arr, 0);
+  }
+  
+  private boolean helper(TreeNode root, int[] arr, int idx) {
+    if (root == null || idx >= arr.length) {
+      return false;
+    }
+    if (root.val != arr[idx]) {
+      return false;
+    }
+    if (root.left == null && root.right == null && idx == (arr.length - 1)) {
+      return true;
+    }
+    return helper(root.left, arr, idx + 1) || helper(root.right, arr, idx + 1);
+  }
+}
