RoughStrings | Topcoder Archive

Problem Statement

Given a string s, its roughness is calculated as follows: Let c1 be the letter that appears most frequently in s, and let c2 be the letter that appears least frequently (c2 must appear at least once). The roughness of s is the number of occurrences of c1 minus the number of occurrences of c2.

You are allowed to modify s by erasing between 0 and n characters, inclusive (see example 1 for clarification). Return the minimum possible roughness that can be achieved by such a modification.

Definition

Class:: RoughStrings
Method:: minRoughness
Parameters:: String, int
Returns:: int
Method signature:: int minRoughness(String s, int n)
(be sure your method is public)

Constraints

s will contain between 1 and 50 characters, inclusive.
s will contain only lowercase letters ('a'-'z').
n will be between 0 and m-1, inclusive, where m is the number of characters in s.

Examples

```
"aaaaabbc"
```
```
1
```
```
Returns: 3
```
We may remove one 'a' or one 'c' to obtain the minimal roughness of 3.
```
"aaaabbbbc"
```
```
5
```
```
Returns: 0
```
One of the ways is to remove 'c' and all occurrences of 'a'.
```
"veryeviltestcase"
```
```
1
```
```
Returns: 2
```

"gggggggooooooodddddddllllllluuuuuuuccckkk"

Returns: 3

"zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz"

Returns: 0

```
"bbbccca"
```
```
2
```
```
Returns: 0
```
Sometimes you may want to remove less than n characters.

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