:orphan:

Permutation in String
=====================

.. highlight:: none

Problem
-------
https://leetcode.com/problems/permutation-in-string/

Given two strings ``s1`` and ``s2``, return ``true`` if ``s2`` contains
a permutation of ``s1``, or ``false`` otherwise.

In other words, return ``true`` if one of ``s1``'s permutations is the
substring of ``s2``.

 

**Example 1:**

::


   Input: s1 = "ab", s2 = "eidbaooo"
   Output: true
   Explanation: s2 contains one permutation of s1 ("ba").

**Example 2:**

::


   Input: s1 = "ab", s2 = "eidboaoo"
   Output: false

 

**Constraints:**

- ``1 <= s1.length, s2.length <= 10``\ :sup:```4```
- ``s1`` and ``s2`` consist of lowercase English letters.

.. highlight:: python

Pattern
-------
Hash Table, Two Pointers, String, Sliding Window

Approaches
----------

.. tab-set::

    .. tab-item:: Sliding Window

        **Code**

        .. literalinclude:: ../problems/medium/permutation-in-string/permutation_in_string__sliding_window.py
            :language: python
            :lines: 9-

        **Test**

        >>> from permutation_in_string__sliding_window import checkInclusion
        >>> checkInclusion("ab", "eidbaooo")
        True
        >>> checkInclusion("ab", "eidboaoo")
        False

        .. autofunction:: permutation_in_string__sliding_window.checkInclusion