Welsh powell coloring

[badumbatish]

Hi there, I'm creating a pull request to merge the Welsh Powell Coloring algorithm into the master branch.

The algorithm returns a std::map<Node, int> result that assigns each node to a color order (assigned by integers).

Users can also query the minimum chromatic order of the graph by querying the highest value from the resulting map

auto result = graph.welshPowellColoring();
auto chromatic_color = std::max_element(result.begin(), result.end(),
                                     [](const auto& lhs, const auto& rhs) {
                                       return lhs.second < rhs.second;
                                     }

The minimum coloring starts from 1 instead of 0.

The algorithm assumes the graph to be undirected. All sources and inspirations are linked in the declaration of the algorithm and test cases.

[ghost]

👇 Click on the image for a new way to code review

Legend

[ZigRazor]

Hi @badumbatish , please resolve conflict so we have the possibility to merge it!

[badumbatish]

Hi there, I forgot to sync my fork with the origin repository. Things should be fixed now @ZigRazor

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (87bee02) 97.55% compared to head (206bc51) 97.58%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #391      +/-   ##
==========================================
+ Coverage   97.55%   97.58%   +0.03%     
==========================================
  Files          85       87       +2     
  Lines        9367     9494     +127     
==========================================
+ Hits         9138     9265     +127     
  Misses        229      229              

Flag	Coverage Δ
unittests	97.58% <100.00%> (+0.03%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.