199 lines
6.6 KiB
Plaintext
199 lines
6.6 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"##### Copyright 2020 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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"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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"metadata": {},
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"source": [
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"# alldifferent_except_0"
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]
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},
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{
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"cell_type": "markdown",
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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/alldifferent_except_0.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/alldifferent_except_0.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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"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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"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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"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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" All different except 0 Google CP Solver.\n",
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"\n",
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" Decomposition of global constraint alldifferent_except_0.\n",
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"\n",
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" From Global constraint catalogue:\n",
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" http://www.emn.fr/x-info/sdemasse/gccat/Calldifferent_except_0.html\n",
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" '''\n",
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" Enforce all variables of the collection VARIABLES to take distinct\n",
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" values, except those variables that are assigned to 0.\n",
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"\n",
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" Example\n",
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" (<5, 0, 1, 9, 0, 3>)\n",
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"\n",
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" The alldifferent_except_0 constraint holds since all the values\n",
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" (that are different from 0) 5, 1, 9 and 3 are distinct.\n",
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" '''\n",
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"\n",
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" Compare with the following models:\n",
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" * Comet: http://hakank.org/comet/alldifferent_except_0.co\n",
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" * ECLiPSe: http://hakank.org/eclipse/alldifferent_except_0.ecl\n",
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" * Tailor/Essence': http://hakank.org/tailor/alldifferent_except_0.eprime\n",
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" * Gecode: http://hakank.org/gecode/alldifferent_except_0.cpp\n",
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" * Gecode/R: http://hakank.org/gecode_r/all_different_except_0.rb\n",
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" * MiniZinc: http://hakank.org/minizinc/alldifferent_except_0.mzn\n",
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" * SICStus_ http://hakank.org/sicstus/alldifferent_except_0.pl\n",
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" * Choco: http://hakank.org/choco/AllDifferentExcept0_test.java\n",
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" * JaCoP: http://hakank.org/JaCoP/AllDifferentExcept0_test.java\n",
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" * Zinc: http://hakank.org/minizinc/alldifferent_except_0.zinc\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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"from __future__ import print_function\n",
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"\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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"# Decomposition of alldifferent_except_0\n",
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"# Thanks to Laurent Perron (Google) for\n",
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"# suggestions of improvements.\n",
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"#\n",
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"\n",
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"\n",
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"def alldifferent_except_0(solver, a):\n",
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" n = len(a)\n",
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" for i in range(n):\n",
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" for j in range(i):\n",
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" solver.Add((a[i] != 0) * (a[j] != 0) <= (a[i] != a[j]))\n",
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"\n",
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"\n",
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"# more compact version:\n",
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"\n",
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"\n",
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"def alldifferent_except_0_b(solver, a):\n",
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" n = len(a)\n",
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" [\n",
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" solver.Add((a[i] != 0) * (a[j] != 0) <= (a[i] != a[j]))\n",
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" for i in range(n)\n",
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" for j in range(i)\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(\"Alldifferent except 0\")\n",
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"\n",
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"# data\n",
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"n = 7\n",
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"\n",
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"# declare variables\n",
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"x = [solver.IntVar(0, n - 1, \"x%i\" % i) for i in range(n)]\n",
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"# Number of zeros.\n",
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"z = solver.Sum([x[i] == 0 for i in range(n)]).VarWithName(\"z\")\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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"alldifferent_except_0(solver, x)\n",
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"\n",
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"# we require 2 0's\n",
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"solver.Add(z == 2)\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[i] for i in range(n)])\n",
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"solution.Add(z)\n",
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"\n",
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"collector = solver.AllSolutionCollector(solution)\n",
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"solver.Solve(\n",
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" solver.Phase([x[i] for i in range(n)], solver.CHOOSE_FIRST_UNBOUND,\n",
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" solver.ASSIGN_MIN_VALUE), [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(n)])\n",
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" print(\"z:\", collector.Value(s, z))\n",
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" print()\n",
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"\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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"\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": 4
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}
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