<ahref="christofides_8h.html">Go to the documentation of this file.</a><divclass="fragment"><divclass="line"><aname="l00001"></a><spanclass="lineno"> 1</span> <spanclass="comment">// Copyright 2010-2018 Google LLC</span></div><divclass="line"><aname="l00002"></a><spanclass="lineno"> 2</span> <spanclass="comment">// Licensed under the Apache License, Version 2.0 (the "License");</span></div><divclass="line"><aname="l00003"></a><spanclass="lineno"> 3</span> <spanclass="comment">// you may not use this file except in compliance with the License.</span></div><divclass="line"><aname="l00004"></a><spanclass="lineno"> 4</span> <spanclass="comment">// You may obtain a copy of the License at</span></div><divclass="line"><aname="l00005"></a><spanclass="lineno"> 5</span> <spanclass="comment">//</span></div><divclass="line"><aname="l00006"></a><spanclass="lineno"> 6</span> <spanclass="comment">// http://www.apache.org/licenses/LICENSE-2.0</span></div><divclass="line"><aname="l00007"></a><spanclass="lineno"> 7</span> <spanclass="comment">//</span></div><divclass="line"><aname="l00008"></a><spanclass="lineno"> 8</span> <spanclass="comment">// Unless required by applicable law or agreed to in writing, software</span></div><divclass="line"><aname="l00009"></a><spanclass="lineno"> 9</span> <spanclass="comment">// distributed under the License is distributed on an "AS IS" BASIS,</span></div><divclass="line"><aname="l00010"></a><spanclass="lineno"> 10</span> <spanclass="comment">// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span></div><divclass="line"><aname="l00011"></a><spanclass="lineno"> 11</span> <spanclass="comment">// See the License for the specific language governing permissions and</span></div><divclass="line"><aname="l00012"></a><spanclass="lineno"> 12</span> <spanclass="comment">// limitations under the License.</span></div><divclass="line"><aname="l00013"></a><spanclass="lineno"> 13</span> </div><divclass="line"><aname="l00014"></a><spanclass="lineno"> 14</span> <spanclass="comment">// ChristofidesPathSolver computes an approximate solution to the Traveling</span></div><divclass="line"><aname="l00015"></a><spanclass="lineno"> 15</span> <spanclass="comment">// Salesman Problen using the Christofides algorithm (c.f.</span></div><divclass="line"><aname="l00016"></a><spanclass="lineno"> 16</span> <spanclass="comment">// https://en.wikipedia.org/wiki/Christofides_algorithm).</span></div><divclass="line"><aname="l00017"></a><spanclass="lineno"> 17</span> <spanclass="comment">// Note that the algorithm guarantees finding a solution within 3/2 of the</span></div><divclass="line"><aname="l00018"></a><spanclass="lineno"> 18</span> <spanclass="comment">// optimum. Its complexity is O(n^2 * log(n)) where n is the number of nodes.</span></div><divclass="line"><aname="l00019"></a><spanclass="lineno"> 19</span> </div><divclass="line"><aname="l00020"></a><spanclass="lineno"> 20</span> <spanclass="preprocessor">#ifndef OR_TOOLS_GRAPH_CHRISTOFIDES_H_</span></div><divclass="line"><aname="l00021"></a><spanclass="lineno"> 21</span> <spanclass="preprocessor">#define OR_TOOLS_GRAPH_CHRISTOFIDES_H_</span></div><divclass="line"><aname="l00022"></a><spanclass="lineno"> 22</span> </div><divclass="line"><aname="l00023"></a><spanclass="lineno"> 23</span> <spanclass="preprocessor">#include "absl/container/flat_hash_map.h"</span></div><divclass="line"><aname="l00024"></a><spanclass="lineno"> 24</span> <spanclass="preprocessor">#include "ortools/base/integral_types.h"</span></div><divclass="line"><aname="l00025"></a><spanclass="lineno"> 25</span> <spanclass="preprocessor">#include "ortools/base/logging.h"</span></div><divclass="line"><aname="l00026"></a><spanclass="lineno"> 26</span> <s
