FindStringBetween | Topcoder Archive

Problem Statement

A valid string is a string of 0 to L lowercase English letters. All strings in this problem are valid strings.

All string comparisons are standard comparisons according to their lexicographic order: the string with a smaller character at the leftmost index on which they differ is smaller (e.g., "car" < "cat" because 'r' < 't') and if X is a proper prefix of Y, X is smaller than Y (e.g., "cat" < "cats").

You are given two valid strings A and B. They are not necessarily distinct.

Return any valid string C such that A < C < B. If there is no such C, return "ERROR" instead (quotes for clarity only).

Definition

Class:: FindStringBetween
Method:: generate
Parameters:: int, String, String
Returns:: String
Method signature:: String generate(int L, String A, String B)
(be sure your method is public)

Notes

X is a proper prefix of Y if X is a prefix of Y and X is shorter than Y.

Constraints

L will be between 1 and 10, inclusive.
A and B will be valid strings.

Examples

```
10
```
```
"cat"
```
```
"elephant"
```
```
Returns: "dog"
```
```
4
```
```
"buzz"
```
```
"byte"
```
```
Returns: "bye"
```
```
7
```
```
"buzz"
```
```
"byte"
```
```
Returns: "buzzard"
```
```
4
```
```
"pier"
```
```
"pies"
```
```
Returns: "ERROR"
```
```
9
```
```
"later"
```
```
"earlier"
```
```
Returns: "ERROR"
```

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