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1221. Split a String in Balanced Strings

Difficulty Topics

Description

Balanced strings are those that have an equal quantity of 'L' and 'R' characters.

Given a balanced string s, split it into some number of substrings such that:

  • Each substring is balanced.

Return the maximum number of balanced strings you can obtain.

 

Example 1:

Input: s = "RLRRLLRLRL"
Output: 4
Explanation: s can be split into "RL", "RRLL", "RL", "RL", each substring contains same number of 'L' and 'R'.

Example 2:

Input: s = "RLRRRLLRLL"
Output: 2
Explanation: s can be split into "RL", "RRRLLRLL", each substring contains same number of 'L' and 'R'.
Note that s cannot be split into "RL", "RR", "RL", "LR", "LL", because the 2nd and 5th substrings are not balanced.

Example 3:

Input: s = "LLLLRRRR"
Output: 1
Explanation: s can be split into "LLLLRRRR".

 

Constraints:

  • 2 <= s.length <= 1000
  • s[i] is either 'L' or 'R'.
  • s is a balanced string.

Solution

split-a-string-in-balanced-strings.py
class Solution:
    def balancedStringSplit(self, s: str) -> int:
        r = l = res = 0

        for c in s:
            if c == "R": r += 1
            else: l += 1

            res += l == r

        return res