9、回文数

链接

fun isPalindrome(x: Int): Boolean {
    if (x < 0) return false
    if (x < 10) return true
    val numStr = x.toString()
    var low = 0
    var high = numStr.length - 1
    while (low < high) {
        if (numStr[low++] != numStr[high--]) return false
    }
    return true
}