동적계획법 보강 코드

dynamicprog.ipynb

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   "cells": [
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "n = 5\n",
      "for i in range(n):\n",
      "    for j in range(i+1, n):\n",
      "        for k in range(j+1, n):\n",
      "            print i, j, k"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "0 1 2\n",
        "0 1 3\n",
        "0 1 4\n",
        "0 2 3\n",
        "0 2 4\n",
        "0 3 4\n",
        "1 2 3\n",
        "1 2 4\n",
        "1 3 4\n",
        "2 3 4\n"
       ]
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "elements = 5\n",
      "\n",
      "def pick(n, picked, to_pick):\n",
      "    if to_pick == 0:\n",
      "        print ' '.join(str(s) for s in picked)\n",
      "        return\n",
      "     \n",
      "    smallest = 0 if len(picked) == 0 else picked[-1] + 1\n",
      "    for i in range(smallest, n):\n",
      "        picked.append(i)\n",
      "        pick(elements, picked, to_pick - 1)\n",
      "        picked.pop()\n",
      "\n",
      "pick(elements, [], 3)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "0 1 2\n",
        "0 1 3\n",
        "0 1 4\n",
        "0 2 3\n",
        "0 2 4\n",
        "0 3 4\n",
        "1 2 3\n",
        "1 2 4\n",
        "1 3 4\n",
        "2 3 4\n"
       ]
      }
     ],
     "prompt_number": 25
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "cities = 'abcd'\n",
      "distances = {'ab': 4, 'bc': 3, 'cd': 8, 'bd': 6, 'ad': 2, 'ac': 7}\n",
      "\n",
      "def get_path_length(path):\n",
      "    routes = [sorted(r) for r in zip(path, path[1:])]\n",
      "    l = sum([distances[''.join(r)] for r in routes])\n",
      "    print l\n",
      "    return l\n",
      "\n",
      "def shortest_path(cur_path):\n",
      "    if len(cur_path) == len(cities):\n",
      "        print cur_path\n",
      "        return get_path_length(cur_path)\n",
      "    ret = 987654321\n",
      "    for city in cities:\n",
      "        if city in cur_path:\n",
      "            continue\n",
      "        cur_path.append(city)\n",
      "        ret = min(ret, shortest_path(cur_path))\n",
      "        cur_path.pop()\n",
      "    return ret\n",
      "\n",
      "shortest_path([])"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "['a', 'b', 'c', 'd']\n",
        "15\n",
        "['a', 'b', 'd', 'c']\n",
        "18\n",
        "['a', 'c', 'b', 'd']\n",
        "16\n",
        "['a', 'c', 'd', 'b']\n",
        "21\n",
        "['a', 'd', 'b', 'c']\n",
        "11\n",
        "['a', 'd', 'c', 'b']\n",
        "13\n",
        "['b', 'a', 'c', 'd']\n",
        "19\n",
        "['b', 'a', 'd', 'c']\n",
        "14\n",
        "['b', 'c', 'a', 'd']\n",
        "12\n",
        "['b', 'c', 'd', 'a']\n",
        "13\n",
        "['b', 'd', 'a', 'c']\n",
        "15\n",
        "['b', 'd', 'c', 'a']\n",
        "21\n",
        "['c', 'a', 'b', 'd']\n",
        "17\n",
        "['c', 'a', 'd', 'b']\n",
        "15\n",
        "['c', 'b', 'a', 'd']\n",
        "9\n",
        "['c', 'b', 'd', 'a']\n",
        "11\n",
        "['c', 'd', 'a', 'b']\n",
        "14\n",
        "['c', 'd', 'b', 'a']\n",
        "18\n",
        "['d', 'a', 'b', 'c']\n",
        "9\n",
        "['d', 'a', 'c', 'b']\n",
        "12\n",
        "['d', 'b', 'a', 'c']\n",
        "17\n",
        "['d', 'b', 'c', 'a']\n",
        "16\n",
        "['d', 'c', 'a', 'b']\n",
        "19\n",
        "['d', 'c', 'b', 'a']\n",
        "15\n"
       ]
      },
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 39,
       "text": [
        "9"
       ]
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     "prompt_number": 39
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     "cell_type": "code",
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