15 puzzle by Kotlin

package demo

fun main(args : Array<String>) {
    val data = array(1,2,3,0,5,6,7,4,9,10,11,8,13,14,15,12);
    var limit:Int = 0;
    var LIMIT_MAX:Int = 20;
    while(limit <= LIMIT_MAX){
        print(limit);
        if(run(data,0,-1,limit)){
            break;
        }
        limit += 1;
    }
}

fun search_white_space_pos(data : Array<Int>):Int{
    for(i in data.indices){
        if(data[i] == 0){
            return i;
        }
    }
    return -1;
}

fun finish(data : Array<Int>):Boolean{
    for(i:Int in data.indices){
    if(i == 15){
        if(data[i] == 0){
            return true;
        }else{
            return false;
        }
    }else{
        if(data[i] == i + 1){
            continue;
        }
        return false;
    }
}
return true;
}

fun is_move_down(white_space_pos:Int):Boolean{
    if(white_space_pos >= 12 && white_space_pos <= 15){
        return false;
    }
    return true;
}
fun is_move_up(white_space_pos:Int):Boolean{
    if(white_space_pos >= 0 && white_space_pos <= 3){
        return false;
    }
    return true;
}
fun is_move_left(white_space_pos:Int):Boolean{
    if(white_space_pos == 0 || white_space_pos == 4 || white_space_pos == 8 || white_space_pos == 12){
        return false;
    }
    return true;
}
fun is_move_right(white_space_pos:Int):Boolean{
    if(white_space_pos == 3 || white_space_pos == 7 || white_space_pos == 9 || white_space_pos == 15){
        return false;
    }
    return true;
}
fun swap(data:Array<Int>,pos1:Int,pos2:Int){
    var temp:Int = data[pos2];
    data[pos2] = data[pos1];
    data[pos1] = temp;
}

fun show(data:Array<Int>){
    for(d in data){
        print(d);
        print(" ");
    }
    println();
}

fun run(data : Array<Int>,depth:Int,previous:Int,limit:Int):Boolean{
    var white_space_pos:Int = search_white_space_pos(data);

    if(depth > limit){

        return false;
    }
    if(finish(data)){
        println("found");
        show(data);
        return true;
    }
    if(previous != 1 && is_move_down(white_space_pos)){
        swap(data,white_space_pos,white_space_pos + 4);
        if(run(data,depth + 1,0,limit)){
            return true;
        }
        swap(data,white_space_pos + 4,white_space_pos);
    }
    if(previous != 0 && is_move_up(white_space_pos)){
        swap(data,white_space_pos,white_space_pos - 4);
        if(run(data,depth + 1,1,limit)){
            return false;
        }
        swap(data,white_space_pos - 4,white_space_pos);
    }
    if(previous != 3 && is_move_left(white_space_pos)){
        swap(data,white_space_pos,white_space_pos - 1);
        if(run(data,depth + 1,2,limit)){
            return false;
        }
        swap(data,white_space_pos - 1,white_space_pos);
    }
    if(previous != 2 && is_move_right(white_space_pos)){
        swap(data,white_space_pos,white_space_pos + 1);
        if(run(data,depth + 1,3,limit)){
            return false;
        }
        swap(data,white_space_pos + 1,white_space_pos);
    }
    return false;
}