Minimum Depth of Binary Tree 二叉树的最小深度

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.

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
 //注意是叶子节点，左右都为空的节点才是
class Solution {
public:
    int minDepth(TreeNode *root) {
        if(root==NULL)
           return 0;
        if(root->left==NULL && root->right==NULL)
           return 1;
        int leftDep,rightDep;
        
        leftDep=minDepth(root->left);
        rightDep=minDepth(root->right);
        if(leftDep==0)
            return rightDep+1;
        else if(rightDep==0)
            return leftDep+1;
        return (leftDep<rightDep?leftDep:rightDep)+1;
    }
};