leetcode3.kt

/**
 * Example:
 * var ti = TreeNode(5)
 * var v = ti.`val`
 * Definition for a binary tree node.
 * class TreeNode(var `val`: Int) {
 *     var left: TreeNode? = null
 *     var right: TreeNode? = null
 * }
 */
import kotlin.math.min
import kotlin.math.max

class Solution {
    fun minDepth(root: TreeNode?): Int {
        if (root == null) return 0
        val leftCount = 1 + minDepth(root.left)
        val rightCount = 1 + minDepth(root.right)
        return if (root.left == null || root.right == null)
            max(leftCount, rightCount)
        else
            min(leftCount, rightCount)
    }
}