Minimum Depth of Binary Tree

Desicription

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.

Solution

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/**
* 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 {
private:
int res = INT_MAX;
void searchTree(TreeNode* root, int depth) {
if(root == NULL)
return ;
if(root->left == NULL && root->right == NULL)
res = min(res, depth);
searchTree(root->left, depth+1);
searchTree(root->right, depth+1);
}
public:
int minDepth(TreeNode* root) {
if(root == NULL)
return 0;
searchTree(root, 1);
return res;
}
};