Program to find length of longest contiguous sublist with same first letter words in Python

Suppose we have a list of lowercase alphabet strings called words. We have to find the length of the longest contiguous sublist where the first letter of each words have the same first letter.

So, if the input is like words = ["she", "sells", "seashells", "on", "the", "sea", "shore"], then the output will be 3, the longest contiguous sublist is ["she", "sells", "seashells"]. The first letter for each words is 's'.

To solve this, we will follow these steps −

• cnt := 1

• maxcnt := 0

• prev_char := blank string

• for each word in words, do

  • if prev_char is empty, then

    • prev_char := first letter of word

  • otherwise when prev_char is same as first letter of word, then

    • cnt := cnt + 1

  • otherwise,

    • prev_char := first letter of word

    • cnt := 1

  • maxcnt := maximum of maxcnt and cnt

• return maxcnt

Example

Let us see the following implementation to get better understanding

def solve(words):
   cnt = 1
   maxcnt = 0
   prev_char = ""
   for word in words:
      if prev_char == "":
         prev_char = word[0]
      elif prev_char == word[0]:
         cnt += 1
      else:
         prev_char = word[0]
         cnt = 1
      maxcnt = max(maxcnt, cnt)
   return maxcnt

words = ["she", "sells", "seashells", "on", "the", "sea", "shore"]
print(solve(words))

Input

["she", "sells", "seashells", "on", "the", "sea", "shore"]

Output

3