Python数据结构与算法分析第2版 - 第1章习题

import numpy as np
sudoku = np.array([
    [0,5,0,0,6,1,0,0,0],
    [0,1,4,0,3,8,0,0,6],
    [6,0,0,0,0,0,7,5,1],
    [8,0,2,0,0,7,3,0,0],
    [4,0,0,0,2,0,0,0,5],
    [0,0,0,4,8,0,0,7,0],
    [0,0,6,3,0,0,1,0,0],
    [0,7,1,0,0,0,9,0,0],
    [0,0,0,6,0,9,0,2,7]
])

def run_app():
    #获取为0的行和列，如果获取不到，说明已经查询到结果，程序退出
# row,col = get_zero()
    try:
        row,col = get_zero()
    except TypeError:
        return
    #从1到9以此实验，看是否满足条件
    for i in range(1,10):
        if can_put(i,row,col):
            #满足条件就开始递归
            sudoku[row,col] = i
            print(row,col)
            print(sudoku)
            run_app()
            #不满足就回溯...
            sudoku[row,col]=0

#获取下一个0的位置
def get_zero():
    try:
        return np.argwhere(sudoku == 0)[0]
    except IndexError:
        #书都中不存在0元素，直接输出结果
        print(sudoku)
        exit(0)

# 判断数字是否可以放入
def can_put(number,row,col):
    return check_row(number,row) and c