searching tree

• The algorithm applies a simple clique finding and weighted coloring to determine lower and upper bounds , and actives exactly one new search tree node at each branching stage which using the information obtained in the weighted coloring to choose a branching vertex , and uses backtracking method to obtain optimum solution
  该算法用团的简单启发式算法提供下界；用加权着色的启发式算法提供上界；在分支阶段，每次只产生一个新的子问题，并利用着色信息来选择分支顶点；最后利用回溯法来检验整体最优性。