Minimum Depth of Binary Tree

Given a binary tree, find its minimum depth.

The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

class Solution {
public:
    int minDepth(TreeNode* root) {
      if(!root) return 0;
      if(!root->left&&!root->right) return 1;
      if(root->left&&root->right) return 1+min(minDepth(root->left),minDepth(root->right));
      if(root->left) return 1+minDepth(root->left);
      if(root->right) return 1+minDepth(root->right);
    }
};