1. A computer-implemented method comprising: using a computer to perform the following: obtaining a first hierarchical structure having a plurality of first nodes; obtaining a second hierarchical structure having a plurality of second nodes; merging the first hierarchical structure and the second hierarchical structure to obtain a merged hierarchical structure having a plurality of third nodes corresponding to at least some of the plurality of first nodes and at least some of the plurality of second nodes; determining a first path from a selected first node in the first hierarchical structure to a root of the merged hierarchical structure, wherein the selected first node corresponds to a selected third node and the first path comprises first path nodes from the plurality of first nodes; determining a second path from a selected second node in the second hierarchical structure to the root, wherein the selected second node corresponds to the selected third node, the second path is different than the first path, and the second path comprises second path nodes from the plurality of second nodes; computing distances between first labels of the first path nodes in the first path and second labels of the second path nodes in the second path to identify pairs of corresponding first path nodes and second path nodes with similar labels, the distances being computed based on numbers of deletions, insertions, or substitutions for transforming the first labels into the second labels; and displaying a user interface comprising: at least part of the merged hierarchical structure, one or more differences between the first hierarchical structure and the second hierarchical structure, the first path including the first path nodes, and the second path including the second path nodes, wherein the first path and the second path are displayed such that the pairs of corresponding first path nodes and second path nodes with similar labels are aligned on the user interface.