24 点 Python 的实现

实现 1 原始

代码

# -*- coding: utf-8 -*-
from __future__ import division

import itertools as it
import random

class Calc24:
    def __init__(self, a, b, c, d):
        fmtList = [
            "((%d%s%d)%s%d)%s%d",  # 1 2 3
            "(%d%s%d)%s(%d%s%d)",  # 1 3 2 == 3 1 2
            "(%d%s(%d%s%d))%s%d",  # 2 1 3
            "%d%s((%d%s%d)%s%d)",  # 2 3 1
            "%d%s(%d%s(%d%s%d))"]  # 3 2 1
        opList = it.product(["+", "-", "*", "/"], repeat=3)
        opList = [opList for opList in opList]
        self.fmtList = fmtList
        self.opList = opList

        self.results = []

        # numList = [9, 2, 4, 8]
        numList = [a, b, c, d]
        numList = it.permutations(numList)
        numList = set(numList)

        # [cal(numList) for numList in numList]
        for n in numList:
            for op in self.opList:
                for fmt in self.fmtList:
                    self._check(fmt, n, op)

    def _check(self, fmt, nums, ops):
        a, b, c, d = nums  # (9, 2, 4, 8)
        op1, op2, op3 = ops
        expr = fmt % (a, op1, b, op2, c, op3, d)

        try:
            result = eval(expr)
        except ZeroDivisionError:
            return
        if result == 24.0000:
            self.results.append(expr)

    def __str__(self):
        r = ""
        for expr in self.results:
            r += expr + " = 24" + "\n"
        return r

    def result_random_one(self):
        i = random.choice(range(self.results.__len__()))
        return self.results[i]

思想