EasySequence | Topcoder Archive

Problem Statement

Petya likes sequences. He has an infinite sequence A[] with the following properties:

A[0], A[1], ..., A[N-1] are given;
A[i]=(A[i-1]+A[i-2]+...+A[i-N])%10 for all i>=N;

Sequence B[] with length M is a substring of A[] if there is such index P that B[0]=A[P], B[1]=A[P+1], ..., B[M-1]=A[P+M-1]. Your task is to find the smallest possible such P. If there is no such index, return -1.

Definition

Class:: EasySequence
Method:: find
Parameters:: int[], int[]
Returns:: int
Method signature:: int find(int[] A, int[] B)
(be sure your method is public)

Constraints

A will contain between 1 and 7 elements, inclusive.
B will contain between 1 and 50 elements, inclusive.
Each element of A will be between 0 and 9, inclusive.
Each element of B will be between 0 and 9, inclusive.

Examples

```
{1,2,3}
```
```
{0,7,8,5}
```
```
Returns: 5
```
Starting with 1,2,3 we have: 1+2+3 = 6, 6 % 10 = 6 2+3+6 = 11, 11 % 10 = 1 3+6+1 = 10, 10 % 10 = 0 6+1+0 = 7, 7 % 10 = 7 1+0+7 = 8, 8 % 10 = 8 0+7+8 = 15, 15 % 10 = 5 7+8+5 = 20, 20 % 10 = 0 1,2,3,6,1,0,7,8,5,0 0,7,8,5 answer = 5
```
{1,2,8}
```
```
{7,4,2,3}
```
```
Returns: -1
```
```
{1,2,3,4,5}
```
```
{4,5}
```
```
Returns: 3
```
```
{1}
```
```
{1,1,1}
```
```
Returns: 0
```

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