Function getUniqueRootIds

source/MRMesh/MRPolylineComponents.cpp:20–36

returns 1. the mapping: FaceId -> Root ID in [0, 1, 2, ...) 2. the total number of roots

/// 1. the mapping: FaceId -> Root ID in [0, 1, 2, ...)
/// 2. the total number of roots
static std::pair<UndirectedEdge2RegionMap, int> getUniqueRootIds( const UndirectedEdgeMap& allRoots, const UndirectedEdgeBitSet& region )
{
    MR_TIMER;
    UndirectedEdge2RegionMap uniqueRootsMap( allRoots.size() );
    int k = 0;
    for ( auto ue : region )
    {
        auto& uniqIndex = uniqueRootsMap[allRoots[ue]];
        if ( uniqIndex < 0 )
        {
            uniqIndex = RegionId( k );
            ++k;
        }
        uniqueRootsMap[ue] = uniqIndex;
    }
    return { std::move( uniqueRootsMap ), k };
}

}