Create binary-tree-coloring-game.cpp

Author: kamyu104

C++/binary-tree-coloring-game.cpp

@@ -0,0 +1,37 @@
+// Time:  O(n)
+// Space: O(h)
+
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    bool btreeGameWinningMove(TreeNode* root, int n, int x) {
+        pair<int, int> left_right;
+        count(root, x, &left_right);
+        const auto& [left, right] = left_right;
+        const auto blue = max(max(left, right),
+                              n - (left + right + 1));
+        return blue > n - blue;
+    }
+
+private:
+    int count(TreeNode *root, int x, pair<int, int> *left_right) {
+        if (!root) {
+            return 0;
+        }
+        const auto& left = count(root->left, x, left_right);
+        const auto& right = count(root->right, x, left_right);
+        if (root->val == x) {
+            left_right->first = left;
+            left_right->second = right;
+        }
+        return left + right + 1;
+    }
+};