StringTransform | Topcoder Archive

Problem Statement

You are given the Strings s and t. Both strings have the same length.

You are allowed to modify s. In each step you may choose two valid indices i and j such that i > j, and change s[i] to s[j]. For example, if s = "abc", you may choose i=2 and j=0, which will change s to "aba".

Return "Possible" (quotes for clarity) if you can change s into t by a sequence of zero or more steps. Otherwise, return "Impossible".

Note that the return values are case-sensitive.

Definition

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

Constraints

s will contain between 1 and 1,000 characters, inclusive.
s and t will be of equal length.
s will contain only lowercase English letters.
t will contain only lowercase English letters.

Examples

```
"abc"
```
```
"aba"
```
```
Returns: "Possible"
```
This is the example from the problem statement. We can change s into t by changing s[2] to s[0].
```
"abc"
```
```
"bbc"
```
```
Returns: "Impossible"
```
Note that in each step i must be greater than j. You are not allowed to choose i=0 and j=1.
```
"topcoder"
```
```
"topcoder"
```
```
Returns: "Possible"
```
The two strings are equal, so we don't have to make any changes.

"rdmcxnnbbe"

"rdrrxrnxbe"

Returns: "Possible"

"rdmcxnnbbe"

"rdqrxrnxbe"

Returns: "Impossible"

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