Day 18: q1: Maximum Difference Between Node and Ancestor #396 cpp cod…

…e done

Day-18/q1: Maximum Difference Between Node and Ancestor/Akansha--C.cpp

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+/**
+ * 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:
+    int maxAncestorDiff(TreeNode* root) {
+         int m = 0;
+        dfs(root, m);
+        return m;
+    }
+
+    private:
+    std::pair<int, int> dfs(TreeNode* root, int& m) {
+        if (root == nullptr) {
+            return {INT_MAX, INT_MIN};
+        }
+
+        auto left = dfs(root->left, m);
+        auto right = dfs(root->right, m);
+
+        int minVal = std::min(root->val, std::min(left.first, right.first));
+        int maxVal = std::max(root->val, std::max(left.second, right.second));
+
+        m = std::max({m, std::abs(minVal - root->val), std::abs(maxVal - root->val)});
+
+        return {minVal, maxVal};
+    }
+};