[LeetCode]#1221. Split a String in Balanced Strings

Environment: Python 3.7

Key technique: dictionary

Balanced strings are those who have equal quantity of ‘L’ and ‘R’ characters.

Given a balanced string s split it in the maximum amount of balanced strings.

Return the maximum amount of splitted balanced strings.

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 = "RLLLLRRRLR"
Output: 3
Explanation: s can be split into "RL", "LLLRRR", "LR", each substring contains same number of 'L' and 'R'.

Example 3:

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

Example 4:

Input: s = "RLRRRLLRLL"
Output: 2
Explanation: s can be split into "RL", "RRRLLRLL", since each substring contains an equal number of 'L' and 'R'

Constraints:

• 1 <= s.length <= 1000
• s[i] = 'L' or 'R'

Analysis:

1. Use dictionary to calculate 'L' and ‘R’ number.
2. If you get L and R number is the same, we get a balance.
3. Re-set dictionary.
4. The example is as below.

Solution:

class Solution:
    def balancedStringSplit(self, s):
        check = {'R': 0, 'L': 0}
        count=0
        for word in s:
            check[word] += 1
            if check['R'] == check['L']:
                count += 1
                check['R'] = 0
                check['L'] = 0
        return count

Submitted result:

Reference:

https://leetcode.com/problems/split-a-string-in-balanced-strings/discuss/555985/Simple-Python-Solution-Using-dict