fun isRotation(s1: String, s2: String): Boolean {
return (s1.length == s2.length) && (s1 + s1).contains(s2)
}
fun main() {
var s1 = "abbc"
var s2 = "cabb"
println(if (isRotation(s1, s2)) "yes" else "no")
s1 = "abbc"
s2 = "bbac"
println(if (isRotation(s1, s2)) "yes" else "no")
}
/*
run:
yes
no
*/