计算具有一个可变字符的子字符串的出现

给定两个字符串A和B，以及整数k是在该字符可以更改为其他任何字符在B指标，任务是检查是否b是子字符串中并打印出多少次数b发生在总共有英文字母的每一个可能的小写字符替换b [k]的后。

例子：

Input: a = “geeks”, b = “ee”, k = 1
Output: 1
Replace b[1] with ‘k’ and “ek” is a sub-string in “geeks”
“ee” is also a sub-string in “geeks”
Hence the total count is 2

Input: a = “dogdog”, b = “dop”, k = 2
Output: 2
Replace b[2] with ‘g’, “dog” is a sub-string in “dogdog” which appears twice.

方法：通过所有的小写字母迭代，并与当前字符替换B中的^第k^个即B [K]字符使字符串B的所有可能的版本的列表。
再算上在原新的字符串B的出现次数，并将其存储在一个变盘点。使用所有小写字符后，输出count 。

下面是上述方法的实现：

# Python3 implementation of the approach
import string
  
# Function to return the count of occurrences
def countOccurrence(a, b, k):    
  
    # Generate all possible substrings to
    # be searched 
    x = []
    for i in range(26):
        x.append(b[0:k] + string.ascii_lowercase[i] + b[k + 1:])
  
    # Now search every substring 'a' and
    # increment count   
    count = 0
    for var in x:
        if var in a:
            count += a.count(var)
              
    return count
  
# Driver code
a, b = "geeks", "ee"
k = 1
print(countOccurrence(a, b, k))

输出：

2