Create 1609. Even Odd Tree (#420)

Author: Chayandas07

1609. Even Odd Tree

@@ -0,0 +1,56 @@
+class Solution {
+public:
+    bool isEvenOddTree(TreeNode* root) {
+        if (root == nullptr)
+            return false;
+
+        queue<TreeNode*> q;
+        q.push(root);
+        int level = -1;
+
+        while (!q.empty()) {
+            level++;
+            int size = q.size();
+            int prev = 0;
+
+            for (int i = 0; i < size; i++) {
+                TreeNode* curr = q.front();
+                q.pop();
+
+                if (level == 0 && curr->val % 2 == 0)
+                    return false;
+
+                if (i == 0) {
+                    if ((level % 2 == 0 && curr->val % 2 == 1)
+                    || (level % 2 == 1 && curr->val % 2 == 0)) {
+                        prev = curr->val;
+                    } else {
+                        return false;
+                    }
+                } else {
+                    if (level % 2 == 1) {
+                        if (curr->val % 2 == 0 && prev > curr->val) {
+                            prev = curr->val;
+                        } else {
+                            return false;
+                        }
+                    } else {
+                        if (curr->val % 2 == 1 && prev < curr->val) {
+                            prev = curr->val;
+                        } else {
+                            return false;
+                        }
+                    }
+                }
+
+                if (curr->left != nullptr)
+                    q.push(curr->left);
+
+                if (curr->right != nullptr)
+                    q.push(curr->right);
+            }
+        }
+
+        return true;
+    }
+};