Create 1457-pseudo-palindromic-paths-in-a-binary-tree.java

Author: sujal-goswami

Diff for: java/1457-pseudo-palindromic-paths-in-a-binary-tree.java

@@ -0,0 +1,29 @@
+class Solution {
+    Map<Integer, Integer> count = new HashMap<>();
+    int odd = 0;
+
+    public int pseudoPalindromicPaths(TreeNode root) {
+        return dfs(root);
+    }
+
+    private int dfs(TreeNode curr) {
+        if (curr == null) {
+            return 0;
+        }
+
+        count.put(curr.val, count.getOrDefault(curr.val, 0) + 1);
+        int oddChange = count.get(curr.val) % 2 == 1 ? 1 : -1;
+        odd += oddChange;
+
+        int res = 0;
+        if (curr.left == null && curr.right == null) {
+            res = (odd <= 1) ? 1 : 0;
+        } else {
+           res = dfs(curr.left) + dfs(curr.right);
+        }
+
+        odd -= oddChange;
+        count.put(curr.val, count.get(curr.val) - 1);
+        return res;
+    }
+}