merging-triplets

Usage

./merge_triplets.py < triplets will merge triplets listed in the file triplets with lookahead 3 and output the size of the resulting set.
./merge_triplets.py -v < triplets will output information on every step of the algorithm, visualizing recursion.
./merge_triplets.py 0 < triplets will use zero lookahead, a.k.a. the blind algorithm as discussed on StackOverflow.
./merge_triplets.py 1 < triplets will use the simple heuristic, a.k.a Level 1: Greedy.
./merge_triplets.py 2 < triplets also for any argument larger than 1, this will use the recursive lookahead algorithm a.k.a. Level 2: Very greedy

./random_triplets.py n will generate n triplets on stdout, with maximum element value about base-3 logarithm of n
./random_triplets.py | ./merge_triplets.py is a convinient way of combining the two scripts

./find_diff.sh n l1 l2 will repeatedly generate sets of n triplets, and compare the results of merges with lookaheads l1 and l2 to find differences. When a difference is found, the script prints details of the event as well as the triplets that caused it and exits. Default values for n, l1 and l2 are 10, 2 and 3 respectively.

./stat_diff.sh n l1 l2 will do the same thing as ./find_diff.sh n l1 l2 except that instead of exiting, it will keep track of differences and continue running with new datasets. Sending an interrupt (Ctrl-C) will cause the script to print the statistics so far and exit. The script will leave behind last_better[12]_triplets files (so long the corresponding datasets have been found) so that they can be analyzed after the script has finished.

These files are examples of triplets which cause different results for different lookaheads, as found by the find_diff.sh script.