Greedy

Transcript

1. Activity Selection: Shortest Shortest duration does not work: 47 / 55
2. Activity Selection: First Start Earliest start time doesn’t work either: 48 / 55
3. Activity Selection: Fewest Overlaps Fewest overlaps doesn’t work either: 49 / 55
4. Activity Selection: Shortest Delay Nor shortest delay to next activity: 50 / 55
5. Activity Selection: Earliest End Time Earliest end time looks good: Note there are equally good alternatives here, but nothing better. But one example does not convince us.. 51 / 55
6. Refute Maleficent’s Claim Ok Maleficient,... I We want you to think about the first activity you picked that we did not. I Can you just swap it out with one of ours that overlaps with it? I If so, just do that (you aren’t getting any extra benefit). I Repeat this swapping until the answer is no... 53 / 55
7. Refute Maleficent’s Claim So now we have... I But we can’t just swap out Maleficent’s activity for ours, so the picture needs to look more like this: Because Maleficent needs some other activity in her choices that conflicts with ours (so she can’t just swap) I But for that to happen, her activity has to end earlier than ours—but we picked greedily based on end time! 54 / 55