Escaping Depressions in LRTS Based on Incremental Refinement of Encoded Quad-Trees

Algorithm 3

Pseudocode of the algorithm to repair and query a node.

(1) RepairANode(, NewState)

(2) if   in the hash table then

(3)  if   is a leaf node then

(4)   .state = NewState;

(5)    .parent;

(6)   while all children of possess the same

     state do

(7)    erase all the children from the table;

(8)    .state NewState, .parent;

(9)    if   is the root node then

(10)     break the while loop;

(11)    end

(12)   end

(13)  else

(14)   .state = NewState;

(15)   for each .child do

(16)    ClearSubTree();

(17)   end

(18)  end

(19) else

(20)  CreateANode(, NewState);

(21) end

(22) ClearSubTree()

(23) if   is not a leaf node then

(24)  for each child do

(25)   ClearSubTree();

(26)  end

(27) else

(28)  erase from the table;

(29) end

(30) CreateANode(, NewState)

(31) ;

(32) while   not in the table and not the root node do

(33)  parent;

(34) end

(35) if    then

(36)  .child new 4 leaf nodes, ;

(37)  for each child do

(38)   if   is an ancestor of or   then

(39)    state = grey;

(40)   else

(41)    state state;

(42)   end

(43)  end

(44) end

(45) state = NewState;

(46) QueryANode()

(47) while   not in the table and not the root node do

(48)  .state;

(49) end

(50) return state;