Leetcode 1332 - Remove Palindromic Subsequences

Note:

  • Because you can remove incontiguous chars, so if s is a palindrome string, return 1, otherwise return 2.

Question:

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:

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

Code:

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/**
* @param {string} s
* @return {number}
*/
var removePalindromeSub = function(s) {
if (isPalindrome(s)) return 1;
return 2;

function isPalindrome(str) {
let left = 0, right = str.length - 1;
while (left < right) {
if (str[left] !== str[right]) return false;
left++;
right--;
}
return true;
}
};