cpp: add “2385. Amount of Time for Binary Tree to Be Infected”

Signed-off-by: Matej Focko <mfocko@redhat.com>

cpp/amount-of-time-for-binary-tree-to-be-infected.cpp

@@ -0,0 +1,43 @@
+/**
+ * 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 {
+    int dfs(TreeNode *root, int start, int &time) {
+        if (root == nullptr) {
+            return 0;
+        }
+
+        int left = dfs(root->left, start, time);
+        int right = dfs(root->right, start, time);
+
+        if (root->val == start) {
+            time = std::max(left, right);
+            return -1;
+        }
+
+        if (left >= 0 && right >= 0) {
+            return 1 + std::max(left, right);
+        }
+
+        auto t = std::abs(left) + std::abs(right);
+        time = std::max(time, t);
+
+        return std::min(left, right) - 1;
+    }
+
+  public:
+    int amountOfTime(TreeNode *root, int start) {
+        int time = 0;
+        dfs(root, start, time);
+        return time;
+    }
+};