Time: 1988 ms (5.09%), Space: 448.5 MB (8.04%) - LeetHub

Author: knockcat

1457-pseudo-palindromic-paths-in-a-binary-tree/1457-pseudo-palindromic-paths-in-a-binary-tree.cpp

@@ -0,0 +1,51 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+ * };
+ */
+class Solution {
+public:
+
+    void helper(TreeNode* root, vector<int> freq, int& cnt)
+    {
+        if(root)
+        {
+            ++freq[root->val];
+            
+            helper(root->left, freq, cnt);
+            helper(root->right, freq, cnt);
+            
+            int odd = 0;
+            
+            if(!root->left and !root->right)
+            {
+                for(int i = 0; i < 10; ++i)
+                {
+                    odd += (freq[i] & 1);
+                }
+                
+                cnt += (odd == 1 or odd == 0);
+            }
+            
+            --freq[root->val];
+        }
+    }
+    
+    int pseudoPalindromicPaths (TreeNode* root) {
+        
+        int cnt = 0;
+        
+        vector<int> freq(10, 0);
+        
+        helper(root, freq, cnt);
+        
+        return cnt;
+        
+    }
+};