function pathLength = GetNearestNeighbourPathLength(cityLocation)
  pathLength = 0;
  nCities = length(cityLocation);
  visitedIxs = [1];
  firstCity = cityLocation(1, :);

  for i=2:nCities
    currentCityIx = visitedIxs(end);
    % calculate distance from this node to every other and sort them
    distances = CalculateDistances(currentCityIx, cityLocation);
    [sortedDistances, indices] = sort(distances);

    % increment index until we find the closest unvisited neighbour
    closestUnvisitedIx = 1;
    while ismember(indices(closestUnvisitedIx), visitedIxs)
      closestUnvisitedIx = closestUnvisitedIx + 1;
    end

    % add the closest unvisited neighbour to the visited list and
    % add the distance to the total path length
    visitedIxs = [visitedIxs; indices(closestUnvisitedIx)];
    pathLength = pathLength + sortedDistances(closestUnvisitedIx);
  end

  % add the length of the final step
  lastCity = cityLocation(visitedIxs(end), :);
  finalStepLength = pdist([firstCity; lastCity], 'euclidean');
  pathLength = pathLength + finalStepLength;

end

function distances = CalculateDistances(fromIx, cityLocation)
  distances = [];
  origin = cityLocation(fromIx, :);

  for i=1:length(cityLocation)
    thisCityLocation = cityLocation(i, :);
    distance = pdist([origin; thisCityLocation], 'euclidean');
    distances = [distances; distance];
  end
end