RemovingDigits | Topcoder Archive

Problem Statement

You are given two Strings, number and digits. Each String contains only digits between 1 and 9, inclusive. For each occurrence of a digit in digits, you must remove a single occurrence of that digit from number. Your goal is to end up with the largest possible remaining number after all the necessary digits are removed. Return this number as a String.

Definition

Class:: RemovingDigits
Method:: maxNumber
Parameters:: String, String
Returns:: String
Method signature:: String maxNumber(String number, String digits)
(be sure your method is public)

Constraints

number will contain between 1 and 50 characters, inclusive.
digits will contain between 0 and n-1 characters, inclusive, where n is the number of characters in number.
Each character in number and digits will be a non-zero digit ('1'-'9').
The number of occurrences of each digit in number will be greater than or equal to the number of occurrences of that digit in digits.

Examples

```
"12345"
```
```
"513"
```
```
Returns: "24"
```
If we remove the digits '5', '3', '1' we get the number 24.
```
"112352"
```
```
"1123"
```
```
Returns: "52"
```
There are two choices. We can either get a "25" or a "52". The largest is "52".
```
"123456654321"
```
```
"612534"
```
```
Returns: "654321"
```
Removing the first half of our number gives us the maximum result.
```
"654321123456"
```
```
"612534"
```
```
Returns: "654321"
```
Removing the last half of our number gives us the maximum result.

"2654982765982365"

"2345978"

Returns: "698265265"

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