README_EN.md

2124. Check if All A's Appears Before All B's

中文文档

Description

Given a string s consisting of only the characters 'a' and 'b', return true if every 'a' appears before every 'b' in the string. Otherwise, return false.

 

Example 1:

Input: s = "aaabbb"
Output: true
Explanation:
The 'a's are at indices 0, 1, and 2, while the 'b's are at indices 3, 4, and 5.
Hence, every 'a' appears before every 'b' and we return true.

Example 2:

Input: s = "abab"
Output: false
Explanation:
There is an 'a' at index 2 and a 'b' at index 1.
Hence, not every 'a' appears before every 'b' and we return false.

Example 3:

Input: s = "bbb"
Output: true
Explanation:
There are no 'a's, hence, every 'a' appears before every 'b' and we return true.

 

Constraints:

• 1 <= s.length <= 100
• s[i] is either 'a' or 'b'.

Solutions

Python3

class Solution:
    def checkString(self, s: str) -> bool:
        return "ba" not in s

Java

class Solution {
    public boolean checkString(String s) {
        return !s.contains("ba");
    }
}

C++

class Solution {
public:
    bool checkString(string s) {
        return s.find("ba") == string::npos;
    }
};

Go

func checkString(s string) bool {
	return !strings.Contains(s, "ba")
}

TypeScript

...