Today I have done leetcode's June LeetCoding Challenge with cpp.

June LeetCoding Challenge 8

Description

Remove Palindromic Subsequences

You are given a string s consisting only of letters 'a' and 'b'. In a single step you can remove one palindromic subsequence from s.

Return the minimum number of steps to make the given string empty.

A string is a subsequence of a given string if it is generated by deleting some characters of a given string without changing its order. Note that a subsequence does not necessarily need to be contiguous.

A string is called palindrome if is one that reads the same backward as well as forward.

Example 1:

Input: s = "ababa"
Output: 1
Explanation: s is already a palindrome, so its entirety can be removed in a single step.

Example 2:

Input: s = "abb"
Output: 2
Explanation: "abb" -> "bb" -> "". 
Remove palindromic subsequence "a" then "bb".

Example 3:

Input: s = "baabb"
Output: 2
Explanation: "baabb" -> "b" -> "". 
Remove palindromic subsequence "baab" then "b".

Constraints:

• 1 <= s.length <= 1000
• s[i] is either 'a' or 'b'.

Solution

class Solution {
  bool isPalindrome(string &s) {
    int len = s.length();
    for(int i = 0; i * 2 < len; ++i) {
      if(s[i] != s[len - 1 - i]) return false;
    }
    return true;
  }
public:
  int removePalindromeSub(string s) {
    if(s.length() == 0) return 0;
    if(isPalindrome(s)) return 1;
    return 2;
  }
};

// Accepted
// 48/48 cases passed (4 ms)
// Your runtime beats 30.61 % of cpp submissions
// Your memory usage beats 97.7 % of cpp submissions (6.1 MB)