   "metadata": {
    "kernelspec": {
     "display_name": "Python 2",
     "language": "python",
     "name": "python2"
    },
    "language_info": {
     "codemirror_mode": {
      "name": "ipython",
      "version": 2
 
</s> remove    "display_name": "Python 2",
 </s> add    "display_name": "Python 3", </s> remove     "version": 2
 </s> add     "version": 3 </s> remove    "pygments_lexer": "ipython2",
   "version": "2.7.10"
 </s> add    "pygments_lexer": "ipython3",
   "version": "3.4.3" </s> remove     "* 'AAABCCDDDD' -> 'A3B1C2D4'"
 </s> add     "* 'AAABCCDDDD' -> 'A3BC2D4'" </s> remove     "## Problem: Compress a string such that 'AAABCCDDDD' becomes 'A3B1C2D4'.  Only compress the string if it saves space.\n",
 </s> add     "## Problem: Compress a string such that 'AAABCCDDDD' becomes 'A3BC2D4'.  Only compress the string if it saves space.\n",
   "name": "python3"
   "metadata": {
    "kernelspec": {
     "display_name": "Python 2",
     "language": "python",
   "name": "python3"
    },
    "language_info": {
     "codemirror_mode": {
      "name": "ipython",
      "version": 2
keep keep keep keep replace keep keep keep keep keep
 Update compress challenge based on #44. 
arrays_strings/compress/compress_challenge.ipynb