题目
分析
递归可求出最小深度,要考虑左子树或右子树为空的情景。
题解
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int minDepth(TreeNode* root) {
if(root == NULL)
return 0;
int leftmin = minDepth(root->left);
int rightmin = minDepth(root->right);
if(leftmin == 0)
return rightmin + 1;
if(rightmin == 0)
return leftmin + 1;
return leftmin < rightmin ? leftmin + 1 : rightmin + 1 ;
}
};