Package g1801_1900.s1898_maximum_number_of_removable_characters

Class Solution

java.lang.Object

g1801_1900.s1898_maximum_number_of_removable_characters.Solution

public class Solution
extends Object

1898 - Maximum Number of Removable Characters.

Medium

You are given two strings s and p where p is a subsequence of s. You are also given a distinct 0-indexed integer array removable containing a subset of indices of s (s is also 0-indexed ).

You want to choose an integer k (0 <= k <= removable.length) such that, after removing k characters from s using the first k indices in removable, p is still a subsequence of s. More formally, you will mark the character at s[removable[i]] for each 0 <= i < k, then remove all marked characters and check if p is still a subsequence.

Return the maximum k you can choose such that p is still a subsequence of s after the removals.

A subsequence of a string is a new string generated from the original string with some characters (can be none) deleted without changing the relative order of the remaining characters.

Example 1:

Input: s = “abcacb”, p = “ab”, removable = [3,1,0]

Output: 2

Explanation: After removing the characters at indices 3 and 1, “abcacb” becomes “accb”.

“ab” is a subsequence of “accb”.

If we remove the characters at indices 3, 1, and 0, “abcacb” becomes “ccb”, and “ab” is no longer a subsequence.

Hence, the maximum k is 2.

Example 2:

Input: s = “abcbddddd”, p = “abcd”, removable = [3,2,1,4,5,6]

Output: 1

Explanation: After removing the character at index 3, “abcbddddd” becomes “abcddddd”.

“abcd” is a subsequence of “abcddddd”.

Example 3:

Input: s = “abcab”, p = “abc”, removable = [0,1,2,3,4]

Output: 0

Explanation: If you remove the first index in the array removable, “abc” is no longer a subsequence.

Constraints:

• 1 <= p.length <= s.length <= 105
• 0 <= removable.length < s.length
• 0 <= removable[i] < s.length
• p is a subsequence of s.
• s and p both consist of lowercase English letters.
• The elements in removable are distinct.

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
int	maximumRemovals(String s, String p, int[] removable)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

maximumRemovals

public int maximumRemovals(String s,
                           String p,
                           int[] removable)