I was waiting at the Barber's shop to get a hair cut and Barber comes up to me and gives me his phone where in he was playing sudoku and apparently was not able to proceed after filling a couple of boxes. I felt like this is my forte as I had won a couple of prizes in sudoku solving competitions before joining college and went on and obliged him. But sadly it took me over 10 mins to solve the complete Sudoku and had to endure a 30 min long hair cut with embarrassment.  After coming back I wrote this code and tried to exactly clone my thought process .