MinimumDepthofBinaryTree.java

/** 
 * 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. 
 */

public class MinimumDepthofBinaryTree {
	public int minDepth(TreeNode root) {
		if (root == null)
			return 0;
		if (root.left == null && root.right == null)
			return 1;
		else {
			int leftDepth = root.left != null ? minDepth(root.left)
					: Integer.MAX_VALUE;
			int rightDepth = root.right != null ? minDepth(root.right)
					: Integer.MAX_VALUE;
			return Math.min(leftDepth, rightDepth) + 1;
		}
	}
}