4. The method of claim 1 , wherein performing the plurality of comparisons comprises: generating a distance matrix that includes a first axis and a second axis, wherein the first axis includes only the nodes in the first subset and the second axis includes only the nodes in the second subset; wherein the nodes in the first subset includes (a) a first node that is at a first level in the first document and (b) a second node that is at a second level in the first document than is different than the first level; based on the hash value computed for said each node, generating a plurality of proposed paths through the distance matrix; selecting, based on one or more criteria, a proposed path from the plurality of proposed paths.
7. The method of claim 4 , wherein the step of selecting, based on one or more criteria, a proposed path from the plurality of proposed paths includes selecting a least cost path from the plurality of proposed paths.