{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def cycleToChromosome(nodes):\n",
    "    \"\"\" Input: A sequence Nodes of integers between 1 and 2n.\n",
    "        Output: The chromosome Chromosome containing n synteny blocks resulting from applying\n",
    "        CycleToChromosome to Nodes.\"\"\"\n",
    "    chromosome = []\n",
    "    for j in range(len(nodes)/2):\n",
    "        if nodes[2*j] < nodes[2*j + 1]:\n",
    "            chromosome.append(nodes[2*j + 1]/2)\n",
    "        else:\n",
    "            chromosome.append(-nodes[2*j]/2)\n",
    "    return chromosome    "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1, -2, -3, 4]"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "nodes = [1, 2, 4, 3, 6, 5, 7, 8]\n",
    "cycleToChromosome(nodes)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "(-1 +2 -3 +4 -5 -6 +7 +8 +9 +10 -11 +12 -13 +14 +15 -16 -17 +18 -19 +20 -21 -22 -23 -24 +25 -26 -27 +28 -29 +30 +31 +32 -33 -34 +35 -36 -37 -38 -39 -40 -41 -42 +43 -44 -45 +46 -47 +48 -49 +50 -51 +52 +53 -54 +55 +56 -57 -58 +59 +60 +61 +62 -63 -64 -65 -66)\n"
     ]
    }
   ],
   "source": [
    "f = open('input/rosalind_ba6g.txt')\n",
    "nodes = map(int, f.read().strip().lstrip('(').rstrip(')').split())\n",
    "ans = cycleToChromosome(nodes)\n",
    "output = '('+' '.join([['', '+'][value > 0] + str(value) for value in ans])+')'\n",
    "print(output)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
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