二叉树叶子数

f(b)表示二叉树的所有叶子结点个数:

f(b) = 0; b == NIL

f(b) = 1;  b为叶子结点；

f(b) = f(b->left) + f(b->right);

int getLeafNodes(Node* root){if (root == NULL)return 0;if (root->left == NULL && root->right == NULL)return 1;return getLeafNodes(root->left) + getLeafNodes(root->right);}

PS：算法基于后续遍历