How hard is LeetCode 1653. Minimum Deletions to Make String Balanced?

LeetCode 1653. Minimum Deletions to Make String Balanced is rated Medium on LeetCode.

What is the time complexity of LeetCode 1653. Minimum Deletions to Make String Balanced?

The Python solution on this page runs in O(n), where n is the length of the string s.

What is the space complexity of LeetCode 1653. Minimum Deletions to Make String Balanced?

The Python solution on this page uses O(1) auxiliary space.

What topics does LeetCode 1653. Minimum Deletions to Make String Balanced cover?

LeetCode 1653. Minimum Deletions to Make String Balanced is tagged Stack, String and Dynamic Programming on LeetCode.

Minimum Deletions to Make String Balanced — LeetCode 1653 Python Solution

MediumStackStringDynamic Programming

Problem: #1653
Pattern: Stack
Reading time: 2 min
Source: leetcode.com

The problem

You are given a string s consisting only of characters 'a' and 'b'. You can delete any number of characters in s to make s balanced.

Example

Input: s = "aababbab"
Output: 2
Explanation: You can either:

Python solution

Python

class Solution:
    def minimumDeletions(self, s: str) -> int:
        n = len(s)
        f = [0] * (n + 1)
        b = 0
        for i, c in enumerate(s, 1):
            if c == 'b':
                f[i] = f[i - 1]
                b += 1
            else:
                f[i] = min(f[i - 1] + 1, b)
        return f[n]

Complexity

Measure	Complexity
Time	O(n), where n is the length of the string s
Space	O(1) auxiliary

Pattern: Stack

When the most recent unresolved thing is the one that matters, use a stack. LeetCode 1653. Minimum Deletions to Make String Balanced is filed here because LeetCode tags it Stack, which is the vocabulary this hub collects.

The stack guide has the Python template for the pattern and the 194 LeetCode problems that use it.

Frequently asked questions

How hard is LeetCode 1653. Minimum Deletions to Make String Balanced?: LeetCode 1653. Minimum Deletions to Make String Balanced is rated Medium on LeetCode.
What is the time complexity of LeetCode 1653. Minimum Deletions to Make String Balanced?: The Python solution on this page runs in O(n), where n is the length of the string s.
What is the space complexity of LeetCode 1653. Minimum Deletions to Make String Balanced?: The Python solution on this page uses O(1) auxiliary space.
What topics does LeetCode 1653. Minimum Deletions to Make String Balanced cover?: LeetCode 1653. Minimum Deletions to Make String Balanced is tagged Stack, String and Dynamic Programming on LeetCode.