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Frequently Asked Questions
This tool uses the Longest Common Subsequence (LCS) algorithm to find the optimal set of matching lines between the two texts, then identifies insertions and deletions relative to that common base. This is the same approach used by the Unix diff command.
No. The diff is computed entirely in your browser using JavaScript. Your text never leaves your device — no data is transmitted anywhere.
The LCS algorithm runs in O(m×n) time and space. This tool works well for texts up to several hundred lines. For very large files, use a command-line tool like diff or git diff which use more efficient algorithms.