A Sudoku puzzle uses a 9 × 9 grid in which each column and row, as well as each of the nine 3 × 3 subgrids, must contain all of the digits 1 · · · 9.

This project consists of designing a multithreaded application that determines whether the solution to a Sudoku puzzle is valid or not.

A thread is a basic unit of CPU utilization. It comprises a thread ID, a program counter, a register set, and a stack. It shares with other threads belonging to the same process its code section, data section, and other operating-system resources, such as open files and signals.

sudoku_validator_naive.c is a naive implementation of the sudoku validator. Here we check all 3 conditions for valid sudoku serially.

sudoku_validator.c creates 3 threads for checking each condition parallelly. It makes use of the Pthreads library which is a POSIX standard defining an API for thread creation and synchronization supported by UNIX and several other operating systems.

To see the results visibly, we use the sleep() function defined in unistd.h. After checking each condition, we pause the execution of the program for 5 seconds.

Since the program is running serially and each function sleeps for 5 seconds, the execution time is about 15 seconds.

Since the conditions are running parallel to each other and each function sleeps for 5 seconds, the execution time is about 5 seconds only.