message: Update maximum-product-of-splitted-binary-tree.cpp
diff: class Solution {
  public:
  int maxProduct(TreeNode* root) {
  - static int MOD = 1e9 + 7;
  + static const int MOD = 1e9 + 7;
  int64_t result = 0;
  dfs(root, dfs(root, 0, &result), &result);
  return result % MOD;
  