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Sudoku Solver

Question​

Given a 9x9 grid containing numbers from 1 to 9, write an algorithm to fill in the missing numbers in the grid such that each row, column, and 3x3 subgrid contains all of the digits from 1 to 9.

Example 1
None

Solution​

all//Sudoku Solver.py


def SudokuSolver(board):
    find = find_empty(board)
    if not find:
        return True
    else:
        row, col = find

    for i in range(1,10):
        if valid(board, i, (row, col)):
            board[row][col] = i

            if SudokuSolver(board):
                return True

            board[row][col] = 0

    return False

def valid(board, num, pos):
    # Check row
    for i in range(len(board[0])):
        if board[pos[0]][i] == num and pos[1] != i:
            return False

    # Check column
    for i in range(len(board)):
        if board[i][pos[1]] == num and pos[0] != i:
            return False

    # Check box
    box_x = pos[1] // 3
    box_y = pos[0] // 3

    for i in range(box_y*3, box_y*3 + 3):
        for j in range(box_x * 3, box_x*3 + 3):
            if board[i][j] == num and (i,j) != pos:
                return False

    return True

def find_empty(board):
    for i in range(len(board)):
        for j in range(len(board[0])):
            if board[i][j] == 0:
                return (i, j)  # row, col

    return None