【leetcode】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==NULL) return 0;
        if(root->left==NULL&&root->right==NULL) return 1;
        int i=minDepth(root->left);
        int j=minDepth(root->right);
       
       if(i==0)
            return j+1;
        if(j==0)
            return i+1;
            
        if(i<=j)
            return i+1;
        else
            return j+1;
    }
};