Patent ID: 8300814

Claim:
An information processing unit comprising: a processor; and a memory, wherein the memory stores instructions that, when executed by the processor, cause the processor to perform the operations of: configuring an entire binary tree made up of n-number of leaf nodes, a root node and a plurality of intermediate nodes different from the root node and the leaf nodes and divide the entire tree into a plurality of base subtrees including n 1/y number of leaf nodes to form a y-level (y is a divisor of log(n)) hierarchical structure such that root nodes of the base subtrees at a lower level coincide with leaf nodes of the base subtree at an upper level, defining a set of leaf nodes located lower than a node w of the entire tree as Aw, defining a leaf node located on i-th left of a certain leaf node v as v( −1 ) and a leaf node located on i-th right as v( +i ) in the leaf nodes of the base subtrees, regarding two leaf nodes u and v (v is on right of u) of the base subtrees, defining a set (u→v) as {Au, Au∪Au ( +1 ), . . . , Au∪ . . . ∪Av}and a set (u←v) as {Av, Av∪Av ( −1 ), . . . , Av∪ . . . ∪Au}, when a leaf node located at a left end is defined as lv′ and a leaf node located at a right end is rv′ in a plurality of leaf nodes located lower than a node v of the base subtrees, correlating a set (l root ′→r root ′) and a set (l root ′ (+1) ←)←r root ′) with a root node root of the base subtree at a top level, correlating a set (lv′→rv′ (−1) and a set (lv′ (+1) (a) ←rv′) with a root node v of the base subtrees at a level other than the top level, if an intermediate node v of each subtree is located on left of its parent node, correlate a set (lv′ (+1) ←rv′) with the intermediate node v, and if an intermediate node v of each subtree is located on right of its parent node, correlate a set (lv′→rv′( −1 )) with the intermediate node v; and generating a directed graph where coordinate points corresponding to subsets included in the set (l root ′→r root ′) or the set (lv′→rv′) are arranged on a horizontal coordinate axis with a degree of inclusion increasing from left to right and a directed edge connecting the coordinate points is set and/or a directed graph where coordinate points corresponding to subsets included in the set (l root ′( +1 )←r root ′) or the set (lv′ (+1) ←rv′) are arranged on a horizontal coordinate axis with a degree of inclusion increasing from right to left and a directed edge connecting the coordinate points is set, for each of the root node and the intermediate node v of the respective base subtrees.