add branching for solving any sudoku
This commit is contained in:
Joseph Hopfmüller
162
sudoku.py
162
sudoku.py
@@ -1,11 +1,16 @@
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# import colorama
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# from termcolor import colored
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from copy import deepcopy
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from random import choice, randrange
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import pandas as pd
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import numpy as np
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import sys
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class cell():
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def __init__(self, row, col):
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self.possible = set([i for i in range(1,10)])
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self.solved = False
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self.solution = 0
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self.prefilled = False
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self.branch = False
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self.row = row
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self.col = col
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@@ -18,11 +23,15 @@ class cell():
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retstr += f'with possible values {self.possible}'
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return retstr
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def set_value(self, value):
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def set_value(self, value, branch=False):
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self.possible = {value}
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self.solution = value
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self.solved = True
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self.prefilled = True
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self.prefilled = not branch
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self.branch = branch
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def cleanup(self):
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self.branch = False
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def remove_value(self, value):
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if not self.solved:
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@@ -54,6 +63,10 @@ class cell():
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class sudoku_grid():
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def __init__(self, prefilled_cells):
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self.grid = [[cell(i,j) for j in range(9)] for i in range(9)]
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self.branches = list()
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self.branch_points = list()
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self.last_hash = None
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self.iteration = 0
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# prefilled_cells is a nested list (9x9) of values (1-9), 0 specifies an empty cell
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try:
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@@ -87,6 +100,8 @@ class sudoku_grid():
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current_val = self.grid[i][j].solution
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if self.grid[i][j].prefilled:
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retstr += f'{current_val}'
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elif self.grid[i][j].branch:
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retstr += f'\033[91m{current_val}\033[00m'
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else:
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retstr += f'\033[92m{current_val}\033[00m'
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else:
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@@ -104,12 +119,24 @@ class sudoku_grid():
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retstr += '\n ╚═══╧═══╧═══╩═══╧═══╧═══╩═══╧═══╧═══╝'
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return retstr
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def iterate(self):
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try:
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self.iterate1()
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self.iterate2()
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self.check_branching()
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self.solvable()
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self.iteration += 1
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except:
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print('No solution found')
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print(self)
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sys.exit()
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# remove values based on solved cells
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def iterate1(self):
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# iterate over all cells
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for i in range(9):
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for j in range(9):
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# # remove posibble values based on solved cells
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for j in range(9):
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# # remove possible values based on solved cells
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current_value = self.grid[i][j].solution
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if current_value:
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for k in range(9):
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@@ -122,6 +149,7 @@ class sudoku_grid():
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current_cell = self.grid[(i//3)*3+(i+k)%3][(j//3)*3+(j+l)%3]
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current_cell.remove_value(current_value) # remove value from current 3x3 box
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# remove values based on possible values in other cells of row/column/square
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def iterate2(self):
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for i in range(9):
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for j in range(9):
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@@ -158,9 +186,41 @@ class sudoku_grid():
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current_cell2 = self.grid[row][col]
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current_set = current_set.union(current_cell2.possible)
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current_cell.collapse(current_set)
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def cleanup(self):
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for i in range(9):
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for j in range(9):
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self.grid[i][j].cleanup()
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def check_branching(self):
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if self.invalid_states():
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self.rollback_branch()
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new_hash = hash(str(self))
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if new_hash == self.last_hash:
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[row, col, e, sols] = self.find_lowest_entropy()
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self.branch(row, col, sols)
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self.last_hash = new_hash
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# copy current solution and branch point (branch_point: row, column, selected_solution)
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def save_branch(self, branch_point):
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self.branches.append(deepcopy(self.grid))
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self.branch_points.append(branch_point)
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# revert latest branch
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def rollback_branch(self):
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solution = self.branches.pop()
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branch_point = self.branch_points.pop()
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self.grid = solution
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current_cell = self.grid[branch_point[0]][branch_point[1]]
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current_cell.remove_value(branch_point[2])
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print('rollback branch')
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def branch(self, row, col, solutions):
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current_cell = self.grid[row][col]
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selected_value = choice(solutions)
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self.save_branch((row, col, selected_value))
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print(f'Branched: ({row},{col}): {current_cell.possible}, chose {selected_value}')
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current_cell.set_value(selected_value, branch=True)
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def find_lowest_entropy(self):
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lowest_i = -1
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@@ -191,8 +251,7 @@ class sudoku_grid():
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return None
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possible = self.grid[row][col].possible
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if len(possible) == 1:
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self.grid[row][col].solved = list(possible)[0]
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self.grid[row][col].solved = list(possible)[0]
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def single_solutions_exist(self):
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for i in range(9):
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@@ -208,8 +267,38 @@ class sudoku_grid():
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if not self.grid[i][j].solved:
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return False
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return True
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def solvable(self):
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if len(self.branches) == 0:
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for i in range(9):
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for j in range(9):
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if len(self.grid[i][j]) == 0:
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raise Exception
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return True
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def invalid_states(self):
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for i in range(9):
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row_list = list()
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col_list = list()
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for j in range(9):
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row_list.append(self.grid[i][j].solution)
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col_list.append(self.grid[j][i].solution)
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if len(self.grid[i][j]) == 0:
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return True
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row_list.sort()
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col_list.sort()
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row_list = [x for x in row_list if x != 0]
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col_list = [x for x in col_list if x != 0]
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row_comp = list(set(row_list))
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col_comp = list(set(col_list))
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row_comp.sort()
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col_comp.sort()
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if row_comp != row_list:
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return True
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if col_comp != col_list:
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return True
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return False
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iteration = 1
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if __name__ == '__main__':
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# colorama.init()
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# prefilled = [ [0,4,9, 7,0,5, 0,0,0],
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@@ -224,26 +313,45 @@ if __name__ == '__main__':
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# [0,6,0, 1,0,0, 0,0,0],
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# [4,0,5, 0,0,0, 3,0,2]]
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prefilled = [ [0,0,7, 0,0,5, 0,0,3],
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[0,0,9, 0,6,0, 0,0,0],
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[3,6,0, 0,0,8, 2,0,0],
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# prefilled = [ [0,0,7, 0,0,5, 0,0,3],
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# [0,0,9, 0,6,0, 0,0,0],
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# [3,6,0, 0,0,8, 2,0,0],
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[0,0,6, 0,0,0, 0,0,0],
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[5,1,0, 0,8,0, 0,0,9],
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[0,0,0, 0,0,2, 0,4,0],
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# [0,0,6, 0,0,0, 0,0,0],
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# [5,1,0, 0,8,0, 0,0,9],
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# [0,0,0, 0,0,2, 0,4,0],
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[0,0,0, 5,0,0, 9,0,0],
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[8,3,0, 0,1,0, 0,0,5],
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[7,0,0, 0,0,0, 0,0,0]]
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# [0,0,0, 5,0,0, 9,0,0],
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# [8,3,0, 0,1,0, 0,0,5],
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# [7,0,0, 0,0,0, 0,0,0]]
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sudoku = sudoku_grid(prefilled)
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prefilled = [ [2,0,4, 0,6,1, 0,0,9],
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[0,1,0, 0,0,4, 0,0,0],
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[0,7,0, 0,0,0, 0,2,0],
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[0,2,0, 0,0,0, 0,0,0],
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[8,0,3, 0,0,7, 0,9,0],
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[0,0,0, 5,0,0, 0,0,6],
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[4,0,9, 0,0,3, 0,8,0],
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[0,0,1, 0,0,0, 0,0,0],
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[0,0,0, 0,7,0, 3,0,0]]
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df = pd.read_csv('sudoku.csv')
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row = randrange(len(df))
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quiz = df.loc[row]['quizzes']
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# print(quiz)
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quiz = list(quiz)
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quiz = [int(x) for x in quiz]
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quiz = np.reshape(quiz, (9, 9)).tolist()
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# sudoku = sudoku_grid(prefilled)
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sudoku = sudoku_grid(quiz)
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print(sudoku)
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while not sudoku.is_solved():
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sudoku.iterate1()
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print(f'Iteration {iteration}a')
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print(sudoku)
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sudoku.iterate2()
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print(f'Iteration {iteration}b')
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print(sudoku)
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iteration += 1
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sudoku.iterate()
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# print(f'Iteration {sudoku.iteration}')
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# print(sudoku)
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sudoku.cleanup()
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print('Solved!')
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print(sudoku)
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