    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "## Problem: Determine if a string is a permutation of another string\n",
      "\n",
      "* [Constraints](#Constraints)\n",
      "* [Test Cases](#Test-Cases)\n",
      "* [Algorithm: Compare Sorted Strings](#Algorithm:-Compare-Sorted-Strings)\n",
      "* [Code: Compare Sorted Strings](#Code:-Compare-Sorted-Strings)\n",
 
</s> remove     "## Problem: Determine if a string is a permutation of another string\n",
 </s> add     "## Problem: Determine if a string is a permutation of another string.\n", </s> remove     "## Problem: Determine if a string s1 is a rotation of another string s2, by calling (only once) a function is_substring\n",
 </s> add     "## Problem: Determine if a string s1 is a rotation of another string s2, by calling (only once) a function is_substring.\n", </s> remove     "## Problem: Determine if a string s1 is a rotation of another string s2, by calling (only once) a function is_substring\n",
 </s> add     "## Problem: Determine if a string s1 is a rotation of another string s2, by calling (only once) a function is_substring.\n", </s> remove     "## Problem: Remove duplicates from a linked list\n",
 </s> add     "## Problem: Remove duplicates from a linked list.\n", </s> remove     "## Problem: Implement an algorithm to determine if a string has all unique characters\n",
 </s> add     "## Problem: Implement an algorithm to determine if a string has all unique characters.\n",
    "## Problem: Determine if a string is a permutation of another string.\n",
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
    "## Problem: Determine if a string is a permutation of another string.\n",
      "\n",
      "* [Constraints](#Constraints)\n",
      "* [Test Cases](#Test-Cases)\n",
      "* [Algorithm: Compare Sorted Strings](#Algorithm:-Compare-Sorted-Strings)\n",
      "* [Code: Compare Sorted Strings](#Code:-Compare-Sorted-Strings)\n",
keep keep keep keep replace keep keep keep keep keep
 Fix challenge titles punctuation (#132) 
arrays_strings/permutation/permutation_solution.ipynb