add string shift checker problem

strings/string_is_shifted.ipynb

@@ -0,0 +1,90 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "9d04d27f",
+   "metadata": {},
+   "source": [
+    "## Problem\n",
+    "Given two strings A and B, return whether or not A can be shifted a number of times to get B.\n",
+    "\n",
+    "For example, if `A = cdeab` and `B = abcde` return true. If `A = xyz and B = xzy` return false.  "
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "097684f2",
+   "metadata": {},
+   "source": [
+    "### Solution\n",
+    "First, we should return false if the first and second string differ in length.\n",
+    "\n",
+    "We can then concatenate one of the strings to itself, like (A + A) and check if B is in the concatenated string.\n",
+    "If the string is shifted, we will find it in the new string."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "3a619761",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def is_shifted(a, b):\n",
+    "    if len(a) != len(b):\n",
+    "        return False\n",
+    "    return b in a + a"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "id": "08ceb2ca",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "True"
+      ]
+     },
+     "execution_count": 2,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "is_shifted(\"cdeab\", \"abcde\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "1117e70c",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.9.7"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}