多執行緒按順序列印數字：

示例結題如下：

A執行緒列印：1

B執行緒列印：2

C執行緒列印：3

A執行緒列印：4

B執行緒列印：5

C執行緒列印：6

.........

怎樣高效率實現？

package com.youzu.got.world

import com.google.common.base.Stopwatch

@Volatile
var runNum = 0
var threadNum = 3
var maxNum = 300000


class MyThread(private val threadName: String, var curNum: Int) : Thread() {

  override fun run() {

    
 
while (true) {
      if (curNum <= runNum) {
        println("$threadName : ${runNum + 1}")
        curNum += threadNum
        runNum++
      }
      if (runNum > maxNum) {
        break
      }
    }
  }
}

fun main() {
  var list = arrayListOf<Thread>()


  for (n in 0 until threadNum) {
    val thread 
 
= MyThread("threadName_$n", n)
    list.add(thread)
  }

  var watch = Stopwatch.createStarted()
  list.forEach {
    it.start()
  }

  list.forEach {
    it.join()
  }
  watch.stop()
  println(watch)

}

無鎖方式實現