208 lines
6.2 KiB
Plaintext
208 lines
6.2 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "markdown",
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"id": "google",
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"metadata": {},
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"source": [
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"##### Copyright 2021 Google LLC."
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]
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},
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{
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"cell_type": "markdown",
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"id": "apache",
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"metadata": {},
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"source": [
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"Licensed under the Apache License, Version 2.0 (the \"License\");\n",
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"you may not use this file except in compliance with the License.\n",
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"You may obtain a copy of the License at\n",
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"\n",
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" http://www.apache.org/licenses/LICENSE-2.0\n",
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"\n",
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"Unless required by applicable law or agreed to in writing, software\n",
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"distributed under the License is distributed on an \"AS IS\" BASIS,\n",
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"WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n",
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"See the License for the specific language governing permissions and\n",
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"limitations under the License.\n"
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]
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},
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{
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"cell_type": "markdown",
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"id": "basename",
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"metadata": {},
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"source": [
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"# circuit"
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]
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},
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{
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"cell_type": "markdown",
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"id": "link",
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"metadata": {},
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"source": [
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"<table align=\"left\">\n",
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"<td>\n",
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"<a href=\"https://colab.research.google.com/github/google/or-tools/blob/master/examples/notebook/contrib/circuit.ipynb\"><img src=\"https://raw.githubusercontent.com/google/or-tools/master/tools/colab_32px.png\"/>Run in Google Colab</a>\n",
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"</td>\n",
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"<td>\n",
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"<a href=\"https://github.com/google/or-tools/blob/master/examples/contrib/circuit.py\"><img src=\"https://raw.githubusercontent.com/google/or-tools/master/tools/github_32px.png\"/>View source on GitHub</a>\n",
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"</td>\n",
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"</table>"
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]
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},
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{
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"cell_type": "markdown",
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"id": "doc",
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"metadata": {},
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"source": [
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"First, you must install [ortools](https://pypi.org/project/ortools/) package in this colab."
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"id": "install",
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"metadata": {},
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"outputs": [],
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"source": [
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"!pip install ortools"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"id": "code",
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"metadata": {},
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"outputs": [],
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"source": [
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"# Copyright 2010 Hakan Kjellerstrand hakank@gmail.com\n",
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"#\n",
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"# Licensed under the Apache License, Version 2.0 (the \"License\");\n",
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"# you may not use this file except in compliance with the License.\n",
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"# You may obtain a copy of the License at\n",
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"#\n",
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"# http://www.apache.org/licenses/LICENSE-2.0\n",
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"#\n",
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"# Unless required by applicable law or agreed to in writing, software\n",
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"# distributed under the License is distributed on an \"AS IS\" BASIS,\n",
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"# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n",
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"# See the License for the specific language governing permissions and\n",
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"# limitations under the License.\n",
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"\"\"\"\n",
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"\n",
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" Decomposition of the circuit constraint in Google CP Solver.\n",
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"\n",
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"\n",
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" Cf Global constraint catalog:\n",
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" http://www.emn.fr/x-info/sdemasse/gccat/Ccircuit.html\n",
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"\n",
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" Solution of n=4:\n",
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" x: [2, 0, 3, 1]\n",
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" x: [3, 0, 1, 2]\n",
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" x: [1, 3, 0, 2]\n",
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" x: [3, 2, 0, 1]\n",
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" x: [1, 2, 3, 0]\n",
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" x: [2, 3, 1, 0]\n",
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"\n",
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" The 'orbit' method that is used here is based on some\n",
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" observations on permutation orbits.\n",
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"\n",
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" Compare with the following models:\n",
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" * MiniZinc: http://www.hakank.org/minizinc/circuit_test.mzn\n",
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" * Gecode: http://www.hakank.org/gecode/circuit_orbit.mzn\n",
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"\n",
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"\n",
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" This model was created by Hakan Kjellerstrand (hakank@gmail.com)\n",
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" Also see my other Google CP Solver models:\n",
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" http://www.hakank.org/google_or_tools/\n",
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"\n",
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"\"\"\"\n",
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"\n",
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"\n",
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"import sys\n",
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"from ortools.constraint_solver import pywrapcp\n",
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"\n",
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"#\n",
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"# circuit(x)\n",
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"# constraints x to be an circuit\n",
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"#\n",
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"# Note: This assumes that x is has the domain 0..len(x)-1,\n",
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"# i.e. 0-based.\n",
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"#\n",
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"\n",
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"\n",
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"def circuit(solver, x):\n",
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" n = len(x)\n",
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" z = [solver.IntVar(0, n - 1, \"z%i\" % i) for i in range(n)]\n",
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"\n",
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" solver.Add(solver.AllDifferent(x))\n",
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" solver.Add(solver.AllDifferent(z))\n",
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"\n",
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" # put the orbit of x[0] in in z[0..n-1]\n",
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" solver.Add(z[0] == x[0])\n",
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" for i in range(1, n - 1):\n",
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" # The following constraint give the error\n",
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" # \"TypeError: list indices must be integers, not IntVar\"\n",
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" # solver.Add(z[i] == x[z[i-1]])\n",
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"\n",
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" # solution: use Element instead\n",
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" solver.Add(z[i] == solver.Element(x, z[i - 1]))\n",
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"\n",
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" #\n",
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" # Note: At least one of the following two constraint must be set.\n",
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" #\n",
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" # may not be 0 for i < n-1\n",
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" for i in range(1, n - 1):\n",
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" solver.Add(z[i] != 0)\n",
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"\n",
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" # when i = n-1 it must be 0\n",
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" solver.Add(z[n - 1] == 0)\n",
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"\n",
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"\n",
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"\n",
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"# Create the solver.\n",
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"solver = pywrapcp.Solver(\"Send most money\")\n",
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"\n",
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"# data\n",
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"print(\"n:\", n)\n",
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"\n",
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"# declare variables\n",
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"# Note: domain should be 0..n-1\n",
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"x = [solver.IntVar(0, n - 1, \"x%i\" % i) for i in range(n)]\n",
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"\n",
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"#\n",
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"# constraints\n",
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"#\n",
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"circuit(solver, x)\n",
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"\n",
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"#\n",
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"# solution and search\n",
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"#\n",
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"solution = solver.Assignment()\n",
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"solution.Add(x)\n",
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"\n",
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"collector = solver.AllSolutionCollector(solution)\n",
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"\n",
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"solver.Solve(\n",
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" solver.Phase(x, solver.CHOOSE_FIRST_UNBOUND, solver.ASSIGN_MIN_VALUE),\n",
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" [collector])\n",
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"\n",
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"num_solutions = collector.SolutionCount()\n",
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"for s in range(num_solutions):\n",
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" print(\"x:\", [collector.Value(s, x[i]) for i in range(len(x))])\n",
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"\n",
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"print()\n",
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"print(\"num_solutions:\", num_solutions)\n",
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"print(\"failures:\", solver.Failures())\n",
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"print(\"branches:\", solver.Branches())\n",
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"print(\"WallTime:\", solver.WallTime())\n",
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"print()\n",
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"\n",
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"n = 5\n"
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]
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}
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],
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"metadata": {},
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"nbformat": 4,
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"nbformat_minor": 5
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}
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