/**
* 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.
*
* Tags: Tree, DFS
*/
class MinimumDepth {
public static void main(String[] args) {
}
/**
* Recursive
* Get minDepth of left and right subtree
* If one side is 0, return the other side plus 1
* Return the smaller one + 1
*/
public int minDepth(TreeNode root) {
if (root == null) return 0;
int left = minDepth(root.left);
int right = minDepth(root.right);
if (left == 0) return right + 1;
if (right == 0) return left + 1;
return Math.min(left, right) + 1; // plus root
}
public class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int x) { val = x; }
}
}