Sleep Sort – sleep sorting, another representative of deterministic strange sorting algorithms.
Works like this:
- Iterates through a list of elements
- Run a separate thread for each loop
- The thread sleeps (sleep) the thread for a while – the value of the element and output the value after sleep
- At the end of the loop, wait until the end of the thread’s longest sleep, display a sorted list
An example code for the sleep sort algorithm in C:
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
typedef struct {
int number;
} ThreadPayload;
void *sortNumber(void *args) {
ThreadPayload *payload = (ThreadPayload*) args;
const int number = payload->number;
free(payload);
usleep(number * 1000);
printf("%d", number);
return NULL;
}
int main(int argc, char *argv[]) {
const int numbers[] = {2, 42, 1, 87, 7, 9, 5, 35};
const int length = sizeof(numbers) / sizeof(int);
int maximal = 0;
pthread_t maximalThreadID;
printf("Sorting: ");
for (int i = 0; i < length; i++) { pthread_t threadID; int number = numbers[i]; printf("%d", number); ThreadPayload *payload = malloc(sizeof(ThreadPayload)); payload->number = number;
pthread_create(&threadID, NULL, sortNumber, (void *) payload);
if (maximum < number) {
maximal = number;
maximalThreadID = threadID;
}
}
printf("\n");
printf("Sorted: ");
pthread_join(maximalThreadID, NULL);
printf("\n");
return 0;
}
In this implementation, I used the usleep function on microseconds with the value multiplied by 1000, i.e. in milliseconds.
The time complexity of the algorithm is O(v. long)
Links
https://gitlab.com/demensdeum/algorithms/ -/tree/master/sortAlgorithms/sleepSort
Sources
https://codoholicconfessions.wordpress.com/2017 /05/21/strangest-sorting-algorithms/
https://twitter.com/javascriptdaily/status/856267407106682880?lang= en
https:// stackoverflow.com/questions/6474318/what-is-the-time-complexity-of-the-sleep-sort