ズンドコキヨシ

The ズンドコキヨシ (Zundoko Kiyoshi) function, also known as キヨシチェック (Kiyoshi check) or ズンドコチェック (Zundoko check), is a meme that originates from a tweet by てくも (@kumiromilk) (Tekumo) on March 9, 2016.

Origin

The function originates from this tweet:

I had a problem "implement and describe your own function" on the examine of lecture of Java, Then I implemented the function to keep outputting either "zun" or "doko" randomly and the sequence of "zun" "zun" "zun" "zun" and "doko" outputs "Ki-yo-shi!" and terminates. Then I got 100% grade and earned a unit.

—てくも (@kumiromilk), March 9, 2016

The name of the function comes from lyrics of the song きよしのズンドコ節 (Kiyoshi no Zundoko Bushi) sung by Kiyoshi Hikawa and fans' cheering when he sings the song.

Spreading

The tweet made many people post the implementation of the function in several programming languages, such as Ruby, Python, Go, and so on.

Variations

The original tweet used three strings to output: "ズン", "ドコ", "キ・ヨ・シ！" in Katakana. Some outputs Romanization of those: "Zun", "Doko", "Kiyoshi!".

Some programming languages have no randomization commands, such as brainfuck, The implementation in the language requires a seed value from input from standard input for PRNG implemented in the function, for example.

Implementations

The following Python script defines the function ズンドコキヨシ().

def ズンドコキヨシ():
    List = []
    import random
    while True:
        if random.randint(0, 1) == 0:
            List.append("ズン")
        else: List.append("ドコ")
        print(List[len(List)-1])
        sublist = ["ズン","ズン","ズン","ズン","ドコ"]
        for idx in range(len(List) - len(sublist) + 1):
            if List[idx: idx + len(sublist)] == sublist:
                res = True
                List.append("キ・ヨ・シ！")
                print("キ・ヨ・シ！")
                break
        if List[len(List)-1] == "キ・ヨ・シ！":
            break