clustering problem 1, 3 go into one group group of genes
until you can not find better solution no matter how you shift chromosomes
GO graph is a kind of graph If there is more than one or no path from root to some node then this is a graph not a tree
change the structure of tree to optimize it
matrix can be converted a graph
many 0 may waste space
purify describe the algorithm in a way the teacher can understand connect to the course run time performance represent the matrix n nlogn Basic explaination