cco99p2.kt

package week3

fun checkMK(v:String):Pair<Int, Int>{
    val split = v.split(" ")
    if(split.size != 2 || split[0].isEmpty() || split[1].isEmpty()) throw Exception("invalid mk-$v-")
    val m = split[0].toIntOrNull() ?: throw IllegalArgumentException("invalid int m")
    if(m !in 1.. 1000) throw Throwable("out of range 1..1000 m: $m")
    val k = split[1].toIntOrNull() ?: throw IllegalArgumentException("invalid int k")
    return m to k
}

fun cco99p2() {
    val input = System.`in`.bufferedReader()

    val datasets = input.readLine().toIntOrNull() ?: throw IllegalArgumentException("invalid int datasets")
    val output = mutableListOf<String>()
    var i = 1
    while(i in 1..datasets){
        val mk = input.readLine()
        val (m, k) = checkMK(mk)
        if(i != 1) output.add("")
        when(k){
            1 -> output.add("1st most common word(s):")
            2 -> output.add("2nd most common word(s):")
            3 -> output.add("3rd most common word(s):")
            else -> output.add("${k}th most common word(s):")
        }

        val words = mutableMapOf<String, Int>()
        var j = 0
        while(j < m){
            val word = input.readLine().lowercase()
            if(word.length > 20) throw Throwable("out of 20 length: $word")
            words[word] = words.getOrPut(word){0} + 1
            j++
        }
        val sort = words.entries.sortedByDescending{it.value}
        j = 0
        var nth = 1
        var prev = sort[0].value
        while(j < sort.size){
            val (key, value) = sort[j]
            if(value < prev){
                if(nth == k) break
                nth++
                prev = value
            }
            if(nth == k) output.add(key)
            j++
        }
        i++
    }
    for(o in output) {
        println(o)
    }
}