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) {} * }; */class Solution {private: int minD=INT_MAX;public:    void dfs(TreeNode* node,int curD){        if(!node) return;        if(!node->left&&!node->right&&curD+1<minD){            minD=curD+1;            return;        }        dfs(node->left,curD+1);        dfs(node->right,curD+1);    }    int minDepth(TreeNode *root) {        if(!root) return 0;        dfs(root,0);        return minD;    }};