tree c295726348f2ad42f37d175a1c052a7ee874ea47
parent e7a3e590edabee731e68d5f19d8af14d7b9a83e4
author Shawn O. Pearce <spearce@spearce.org> 1285101707 -0700
committer Shawn O. Pearce <spearce@spearce.org> 1285380609 -0700

Implement HistogramDiff

HistogramDiff is an alternative implementation of patience diff,
performing a search over all matching locations and picking the
longest common subsequence that has the lowest occurrence count.
If there are unique common elements, its behavior is identical to
that of patience diff.

Actual performance on real-world source files usually beats
MyersDiff, sometimes by a factor of 3, especially for complex
comparators that ignore whitespace.

Change-Id: I1806cd708087e36d144fb824a0e5ab7cdd579d73
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>