- 1 current stop: learning
- 2 upcoming
- 3 upcoming
- 4 upcoming
- 5 upcoming
Finish after stop 5
Stop 1 of 5 · Coin counter at the market
Trick to keep in mind+3 XP
Greedy grabs the biggest now; DP tries every coin at every amount.
Greedy never looks back, so one big early choice can leave an awkward remainder. With coins 1, 7 and 10 and a target of 14, taking 10 first needs four 1s, five coins in total, while 7 + 7 does it in two. Trying every coin per amount, as DP does, cannot be fooled this way.
Read it once, then a question tests whether the trick stuck.