Minimum-Depth-of-Binary-Tree

##Minimum Depth of Binary Tree

class Solution:

# @param root, a tree node
# @return an integer
def minDepth(self, root):
    if not root:
        return 0
    if not root.left and root.right:
        return self.minDepth(root.right) +1
    if root.left  and not root.right :
        return self.minDepth(root.left) +1
    return min(self.minDepth(root.left), self.minDepth(root.right)) +1