lintcode-二叉树的最小深度-155

/**
* Definition of TreeNode:
* class TreeNode {
* public:
*     int val;
*     TreeNode *left, *right;
*     TreeNode(int val) {
*         this->val = val;
*         this->left = this->right = NULL;
*     }
* }
*/
class Solution {
public:
int backtracing(TreeNode *root){
if(!root)
return INT_MAX;
if(!root->left&&!root->right)
return 1;
return min(backtracing(root->left),backtracing(root->right))+1;
}

int minDepth(TreeNode *root) {
if(!root)
return 0;
return backtracing(root);
}
};