Bullets | Topcoder Archive

Problem Statement

Each gun leaves a unique set of scratches, sort of like a fingerprint, on every bullet that fires through its chamber. These scratch marks are used widely in forensic investigations of crime scenes.

Given a list of guns and the scratch marks that they leave, and the scratch marks on a bullet, return the element number (0-based) of the gun which fired the bullet.

In order for a bullet to match the gun, the gun must leave just as many scratches as are on the bullet, with the same intervals between scratches. For example, the scratch marks:

"| |||  |   |"
"| |||  |   |"
match, but
"| |||  |   |"
"||| |  |   |"
do not.

Note that since bullets are round, the scratch marks wrap around. Therefore:

"|| ||| | "
" | || |||"

match (since it's the same scratch marks, only starting at a different location).

If no gun matches the bullet, return -1.

Definition

Class:: Bullets
Method:: match
Parameters:: String[], String
Returns:: int
Method signature:: int match(String[] guns, String bullet)
(be sure your method is public)

Notes

Gun markings cannot be flipped. That is, "|||| ||| || |" doesn't match "| || ||| ||||".

Constraints

guns will contain between 0 and 50 elements, inclusive.
each element of guns will have the same length as bullet.
bullet will have length between 5 and 50, inclusive.
bullet and each element of guns can contain only the pipe character '|' and spaces.
at most one gun will match the bullet.

Examples

{"| | | |","|| || |"," ||||  "}

"|| || |"

Returns: 1

```
{"|||   |","| | || "}
```
```
"||||   "
```
```
Returns: 0
```
Notice that index 0 is the same scratch pattern, just shifted.

{"|| || ||","| | | | ","||||||||"}

"||| ||| "

Returns: -1

No gun matches the scratches.

```
{}
```
```
"| | | |"
```
```
Returns: -1
```

{"|| || ||","| | | | ","||| ||| ","||||||||"}

"|| ||| |"

Returns: 2

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