7 Tiny Code Gems That Pack Massive Power: From Shuffle to Fast Inverse Square Root

1. No Code

Project address: https://github.com/kelseyhightower/nocode. This GitHub project, now with 34k stars, demonstrates a lightweight cross‑platform, fully automatic tool that requires zero source code. It uses an “indescribable” high‑level syntax to provide one‑click detection, compilation, packaging, installation and execution.

2. Shuffle Algorithm

A two‑line implementation that generates a uniformly random permutation of n elements, ensuring each element has equal probability of appearing in any position.

for(int i = n - 1; i >= 0; i--)
    swap(arr[i], arr[rand(0, i)]) // rand(0, i) generates a random integer in [0, i]

3. Sleep Sort

The algorithm creates n threads, each associated with one of the n numbers. Each thread sleeps for a duration proportional to its number, then prints the number when it wakes, resulting in an ordered output.

public class SleepSort {
    public static void main(String[] args) {
        int[] ints = {1,4,7,3,8,9,2,6,5};
        SortThread[] sortThreads = new SortThread[ints.length];
        for (int i = 0; i < sortThreads.length; i++) {
            sortThreads[i] = new SortThread(ints[i]);
        }
        for (int i = 0; i < sortThreads.length; i++) {
            sortThreads[i].start();
        }
    }
}
class SortThread extends Thread {
    int ms = 0;
    public SortThread(int ms) { this.ms = ms; }
    public void run() {
        try {
            sleep(ms*10+10);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println(ms);
    }
}

4. “AI Core” One‑Liner

A single‑line Python loop that reads input, removes Chinese question particles, and prints the modified text, touted as a “billion‑yuan AI core”.

while True:
    print(input('').replace('吗','').replace('？','！'))

5. Get Tomorrow’s Timestamp

// talent talent
thread.sleep(86400*1000L);

6. Fast Inverse Square Root (0x5f375a86)

This famous magic number originates from the Quake III fast inverse square‑root algorithm. The core operation is: i = 0x5f3759df - (i >> 1); // what the fuck? Researchers later refined the constant to 0x5f37642f and even 0x5f375a86, achieving marginally better accuracy.

7. Hello World

Every programmer has written a “Hello World” program in some language.

Feel free to share other tiny yet powerful code examples in the comments.