Method depth

543. Diameter of Binary Tree/Solution.cpp:27–32

    Solution():cnt(0) {}

    int depth(TreeNode * root) {
        if (root == NULL) return 0;
        int l = depth(root->left), r = depth(root->right);
        if (l + r > cnt) cnt = l + r;
        return max(l, r) + 1;
    }

    int diameterOfBinaryTree(TreeNode* root) {
        depth(root);