Modify the String

Given a string input_str of length n, choose any character that occurs at least twice and delete any one occurrence. Repeat this until all remaining characters are distinct. Return the lexicographically maximum string that can be formed this way.

Example

input_str = "aabcb"

The length of the string, n = 5. Some of the strings that can be formed are:

• "acb" – delete the first occurrences of 'a' and 'b'
• "abc" – delete the first occurrence of 'a' and the second occurrence of 'b'

It can be proven that the lexicographically maximum string that can be obtained is "acb".

Function Description

Complete the function getString in the editor below.

getString has the following parameters:

• string input_str: a string of length n

Returns

• string: the result of the operations, as described

Constraints

• input_str contains only lowercase English letters
• 1 ≤ n ≤ 10^5

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Count Binary Substrings

A binary string is a string consisting only of 0s and 1s. A substring is a contiguous group of characters within a string.

Given a binary string, find the number of substrings that contain an equal number of 0s and 1s and all the 0s and 1s are grouped together. Note that duplicate substrings are also counted in the answer. For example, "0011" has two overlapping substrings that meet the criteria: "0011" and "01".

Example

s = "011001"

The substrings "01", "10", "1100", and "01" have equal numbers of 0s and 1s with all 0s and 1s grouped consecutively. Hence, the answer is 4. Note that the substring "0110" has an equal number of 0s and 1s but is not counted because not all 0s and 1s are grouped together.

Function Description

Complete the function getSubstringCount in the editor below.

getSubstringCount has the following parameter(s):

• s: a binary string

Returns

• int: the number of substrings that meet the criteria

Constraints

• 1 ≤ length of s ≤ 10^5
• The string s consists of 0s and 1s only

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