Concurrent Sudoku solver in GO

This program attempts to solve easy level sudoku puzzles using goroutines in go.

Approach

• A gouroutine is created for each un-numbered cell with a state which is a map that holds all the 1 to 9 digits.
• The goroutines will check their horizontal, vertical and 3X3 grid for available numbers and remove them from the state.
• As the state gets left with only one number, the gorutine will write the number in the sudoku (shared 2D 9X9 array) and Broadcast to all the waiting goroutines.
• Otherwise current goroutine will also wait for other goroutines to broadcast.
• If all the alive goroutines goes to waiting state the sudoku cannot be solved by this program.