国王与100个囚犯

def day = 0, counter = 0, bigBrother, prisoner, on, log = [:]
while(counter < 100) {
    prisoner = new Random().nextInt(100)
    if(day == 0) {
        bigBrother = prisoner       
    }
    day++
    if(on) {
        if(prisoner != bigBrother) {
            if(!log[prisoner]) {
                log[prisoner] = true
                on = false   
            }
        }
    } else {
        if(prisoner == bigBrother) {
            counter++
            on = true
            if(day == 1) {
                println "One prisoner(big brother himself) is out and in"
            } else {
                println "On day ${day}, when big brother is out seeing the light off, he is sure that ${counter} prisoners have been out and in"
            }
        }
    }
}
println "It took ${day} days(=${day/365} years)."
println "${day>365*30?'We\'re too old to go home(So is the King). We\'d rather stay here in prison until we die.':'Let\'s go home.'}"

One prisoner(big brother himself) is out and in
...
On day 10334, when big brother is out seeing the light off, he is sure that 100 prisoners have been out and in
It took 10334 days(=28.3123287671 years).
Let's go home.