StringTransformationEasy | Topcoder Archive

Problem Statement

You have a sequence of red and green balls. The sequence is described by the String s: red balls are denoted 'R' and green ones 'G'. You would like to transform s into the target String t.

The only transformation allowed looks as follows: Let p,q,r,s be four consecutive balls. If balls q and r have the same color and at the same time balls p and s have different colors, you may remove the balls q and r.

Formally, you may choose an index i such that s[i+1] = s[i+2] and at the same time s[i] != s[i+3]. If you do, you may remove the characters at indices i+1 and i+2 from s.

Return "YES" (quotes for clarity) if there is a sequence of zero or more transformations that converts s into t. Otherwise, return "NO".

Definition

Class:: StringTransformationEasy
Method:: getResult
Parameters:: String, String
Returns:: String
Method signature:: String getResult(String s, String t)
(be sure your method is public)

Constraints

s and t will contain between 1 and 2,500 characters.
s and t will consist only of characters R and G.

Examples

```
"RRRRGGG"
```
```
"RRG"
```
```
Returns: "YES"
```
```
"RRR"
```
```
"RRR"
```
```
Returns: "YES"
```
```
"RRRGGRRRRGGG"
```
```
"RGGRRRRG"
```
```
Returns: "YES"
```
```
"RRGG"
```
```
"RRGGGG"
```
```
Returns: "NO"
```
```
"GGGG"
```
```
"GG"
```
```
Returns: "NO"
```

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