minimum-depth-of-binary-tree

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.



/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */

public class Solution {
    public int run(TreeNode root) {
        if (root == null) {
            return 0;
        }
        int length1 = run(root.left);
        int length2 = run(root.right);
        if (length1 == 0 || length2 == 0) {
            return length1 + length2 + 1;
        }
        return Math.min(length1, length2) + 1;
    }
}