from utils import *

def reduce_puzzle(values):
    stalled = False
    count = 1
    
    while not stalled:
        # Check how many boxes have a determined value
        solved_values_before = len([box for box in values.keys() if len(values[box]) == 1])

        # Your code here: Use the Eliminate Strategy
        values = eliminate(values)
        
        # Your code here: Use the Only Choice Strategy
        values = only_choice(values)
        
        # Check how many boxes have a determined value, to compare
        solved_values_after = len([box for box in values.keys() if len(values[box]) == 1])
        
        # If no new values were added, stop the loop.
        stalled = solved_values_before == solved_values_after
        
        # Stop looping if the puzzle is solved.
        if solved_values_after == len(values):
            #print('Solution found after ' + str(count) + ' iterations.')
            stalled = True
        
        # Sanity check, return False if there is a box with zero available values:
        if len([box for box in values.keys() if len(values[box]) == 0]):
            return False
            
        count = count + 1
            
    return values