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2027. Minimum Moves to Convert String

Difficulty Topics

Description

You are given a string s consisting of n characters which are either 'X' or 'O'.

A move is defined as selecting three consecutive characters of s and converting them to 'O'. Note that if a move is applied to the character 'O', it will stay the same.

Return the minimum number of moves required so that all the characters of s are converted to 'O'.

 

Example 1:

Input: s = "XXX"
Output: 1
Explanation: XXX -> OOO
We select all the 3 characters and convert them in one move.

Example 2:

Input: s = "XXOX"
Output: 2
Explanation: XXOX -> OOOX -> OOOO
We select the first 3 characters in the first move, and convert them to 'O'.
Then we select the last 3 characters and convert them so that the final string contains all 'O's.

Example 3:

Input: s = "OOOO"
Output: 0
Explanation: There are no 'X's in s to convert.

 

Constraints:

  • 3 <= s.length <= 1000
  • s[i] is either 'X' or 'O'.

Solution

minimum-moves-to-convert-string.py
class Solution:
    def minimumMoves(self, s: str) -> int:
        s = list(s)
        n = len(s)
        res = i = 0

        while i < n:
            hasX = False
            if s[i] == 'X':
                for j in range(3):
                    if i + j < n and s[i + j] == 'X':
                        hasX = True
                        s[i + j] = 'O'
                    # print(s)
                if hasX:
                    res += 1
                i += 3
            else:
                i += 1

        return res