solve.cpp

#include <queue>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
};
class Solution {
public:
	int minDepth2(struct TreeNode *root) {
		if (root == NULL)
			return 0;
		if (root->left == NULL && root->right == NULL)
			return 1;
		if (root->left == NULL && root->right != NULL)
			return minDepth(root->right) + 1;
		if (root->left != NULL && root->right == NULL)
			return minDepth(root->left) + 1;
		return min(minDepth(root->left), minDepth(root->right));
	}
	int minDepth(struct TreeNode *root) {
		if (root == NULL)
			return 0;
		if (root->left && root->right)
			return min(minDepth(root->left), minDepth(root->right)) + 1; 
		else if (root->left)
			return minDepth(root->left) + 1;
		else
			return minDepth(root->right) + 1;
	}
};
void mk_children(TreeNode *root, int left, int right)
{
	root->left = new TreeNode(left);
	root->right = new TreeNode(right);
}
void mk_children(TreeNode *root, TreeNode *left, TreeNode *right)
{
	root->left = left;
	root->right = right;
}
int main(int argc, char **argv)
{
	Solution solution;
	TreeNode *root = new TreeNode(1);
	mk_children(root, new TreeNode(2), nullptr);
	cout << solution.minDepth(root) << endl;
	return 0;
}