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# Padovan sequence in core Java

, 12 Dec 2011 CPOL
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Padovan sequence in core Java
Padovan series are positive integers obtained by the following process: The Padovan series is the sequence of integers P(n) defined by the initial values P(0) = P(1) = P(2) = 1, and the recurrence relation P(n) = P(n - 2) + P(n - 3).
Write a program to generate the Padovan series from n to m.

Constraints:
• n >=0 and m <=49.
• m >= n.
If the given inputs are invalid or out of range, then return `-1`.

Example 1:
Input
from = 5
to = 10

Output:
returns {3, 4, 5, 7, 9, 12}

Explanation:

```P(0) = P(1) = P(2) = 1, and the recurrence relation P(n) = P(n - 2) + P(n - 3).
p(5) = p(5-2) + p(5-3)
= p(3) + p(2) -------- (1)
p(3) = p(3-2) + p(3-1)
= p(1) + p(2)
= 1 + 1
= 2
Substitute in (1)
p(5) = 2 + 1
= 3 ```
Similarly the recurrence should continue for the remaining positions.

Example 2:
Input
from = 45
to = 60

Output
Returns {-1}

CODE TO IMPLEMENT THIS:

```import java.util.Scanner;
import java.util.ArrayList;

{
public static void main(String[] arg)
{
Scanner read = new Scanner(System.in);
System.out.println("Enter starting no. : ");
int start = read.nextInt();
System.out.println("Enter ending no. : ");
int end = read.nextInt();
int[] ans = getSeries(start, end);
System.out.println("Padovan series : ");
for (int a : ans)
System.out.print(a + " ");
}

public static int[] getSeries(int s, int e)
{
ArrayList<Integer> list = new ArrayList<Integer>();
int i, j = 0;
for (i = s; i <= e; i++, j++)
int[] ans = new int[j];
for (i = 0; i < j; i++)
ans[i] = list.get(i);
return ans;
}

public static int getPadovan(int p)
{
if (p == 0 || p == 1 || p == 2)
return 1;
return (getPadovan(p - 2) + getPadovan(p - 3));
}
}```

http://en.wikipedia.org/wiki/Padovan_sequence [Check this link for get the information on Padovan Series.]

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