e-olymp
Problems

A Needle in the Haystack

A Needle in the Haystack

Write a program that finds all occurences of a given pattern in a given input string. This is often referred to as finding a needle in a haystack. The program has to detect all occurences of the needle in the haystack.

Input

The input consists of a number of test cases. Each test case is composed of three lines, containing:

  • the length of the needle,
  • the needle itself,
  • the haystack.

The length of the needle is only limited by the memory available to your program, so do not make any assumptions - instead, read the length and allocate memory as needed. The haystack is not limited in size, which implies that your program should not read the whole haystack at once.

The test cases come one after another, each occupying three lines, with no additional space or line breaks in between.

Output

For each test case your program should output all positions of the needle's occurences within the haystack. If a match is found, the output should contain the position of the first character of the match. Characters in the haystack are numbered starting with zero.

For a given test case, the positions output should be sorted in ascending order, and each of these should be printed in a separate line. For two different test cases, the positions should be separated by an empty line.

Time limit 1 seconds
Memory limit 122.17 MiB
Input example #1
2
na
banananobano
6
foobar
foo
9
foobarfoo
barfoobarfoobarfoobarfoobarfoo
Output example #1
2
4


3
9
15
21

Example description: Note the double empty line in the output, which means that no match was found for the second test case