1332.go

// Source: https://leetcode.com/problems/remove-palindromic-subsequences
// Title: Remove Palindromic Subsequences
// Difficulty: Easy
// Author: Mu Yang <http://muyang.pro>

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// 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'.
//
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

package main

// If s is a palindromic, then we only need 1 steps.
// Otherwise, we need only 2 steps by removing all 'a' and removing all 'b'.
func removePalindromeSub(s string) int {
	l := len(s) - 1
	for i := 0; i <= l/2; i++ {
		if s[i] != s[l-i] {
			return 2
		}
	}
	return 1
}