Minimum Depth of Binary Tree @LeetCode

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.

	package leetcode.tree;
	/**
	* Solution: Same to MaxPath. Divide and Conquer.
	* Difference here is it only count leaf node that root.left == null && root.right == null
	* if not, discard. So we can't return 0 when root == null. We need a larget number to make it discard.
	*
	* There's case root == null. return 0. If not, we could use minDepth function directly like maxPath.
	*
	* @author jeffwan
	* @date Apr 14, 2014
	*/
	public class MinDepth {
	public int minDepth(TreeNode root) {
	if (root == null) {
	return 0;
	}
	return getMin(root);
	}
	public int getMin(TreeNode root) {
	if (root == null) {
	return Integer.MAX_VALUE;
	}
	if (root.left == null && root.right == null) {
	return 1;
	}
	return Math.min(getMin(root.left), getMin(root.right)) + 1;
	}
	private class TreeNode {
	int val;
	TreeNode left;
	TreeNode right;
	TreeNode(int x) {val = x; };
	}
	}

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