Question

我正在做一个要求我使用函数的赋值工作，该函数带有两个参数：字符串形式的整数（例如'1921'）和整数k（例如2）。该函数返回的最大回文整数可以最多可以将输入数字的k位更改为任何其他数字0-9来找到。

例如，在1921年最多进行两次更改，最大回文数为1991（一次更改为2-> 9）。如果进行了三处更改，我们将从1921年变为9999，这是四位数可能的最高整数值。

我相信我正在使用的代码检查该数字是否为回文式，但是并不能给我最大的回文式。

使用的代码：

def Is_palindrome(str):
    x = 0 
    for i in range (len(str)/2):
        if (str[x]) == (word[len(str)-x-1]):
            x+=1
        if x == (len(str)/2):
            return True
    return False

def longest_palindrome(str):
    lst = str.split() 
    palindromes = [] #List that contains the palindromes
    long_len = 0 #Length of the longest palindrome
    longest = "" #The actual longest palindrome
    for i in lst: 
        if Is_palindrome(i): #If the str is a palindrome
            palindromes.append(i) #Add it to the palindrome list
    for i in palindromes: #Loop through the palindrome list
        if len(i) > long_len: #If the palindrome is longer than the 
longest one
            longest = i #Set it as the longest one
            longest_len = len(i) # Set the length of the longest one to 
the length of this one
    return longest

如果您有任何建议，请告诉我！！预先感谢。

Answer 1

请尝试以下代码：

import sys

def maximumPalinUsingKChanges(str, k):
    palin = []

    a = 0
    b = len(str)

    while (a < b):
        palin.append(str[a])
        a = a + 1

    # Iinitialize l and r by leftmost and
    # rightmost ends
    l = 0
    r = len(str) - 1

    #  first try to make string palindrome
    while (l < r):
        # Replace left and right character by
        # maximum of both
        if (str[l] != str[r]):
            palin[l] = max(str[l], str[r])
            palin[r] = max(str[l], str[r])
            k = k - 1
        l = l + 1
        r = r - 1    

    # If k is negative then we can't make
    # string palindrome
    if (k < 0):
        print("Not possible")
        return "Not possible"

    l = 0
    r = len(str) - 1

    while (l <= r):
        # At mid character, if K>0 then change
        # it to 9
        if (l == r):
            if (k > 0):
                palin[l] = '9'

        # If character at lth (same as rth) is
        # less than 9
        if (palin[l] < '9'):
            #If none of them is changed in the
            #  previous loop then subtract 2 from K
            # and convert both to 9 
            if (k >= 2 and palin[l] == str[l] and palin[r] == str[r]):
                k -= 2
                palin[l] = '9'
                palin[r] = '9'

            #  If one of them is changed in the previous
            #  loop then subtract 1 from K (1 more is
            #  subtracted already) and make them 9  
            elif (k >= 1 and (palin[l] != str[l] or palin[r] != str[r])):
                k = k - 1
                palin[l] = '9'
                palin[r] = '9'

        l = l + 1
        r = r - 1

    print(''.join(palin))
    return ''.join(palin)

确保k是整数而不是字符串

如何检查最大可能的回文整数

1 个答案: