Arrays

Pointers, windows and in-place tricks, drawn out step by step.

1. 1Array BasicsOne block of memory, instant access to any slot.4m
2. 2Two PointersTwo indexes closing in beat one loop nesting another.5m
3. 3Sliding WindowReuse the last answer instead of recomputing it.5m
4. 4Prefix SumsPay once up front, answer range queries instantly.5m
5. 5In-Place ReversalFlip an array with one temp variable, not a copy.4m
6. 6Move ZeroesPush the junk to the back without losing the order.5m
7. 7Container With Most WaterThe shorter wall decides. So move the shorter wall.6m
8. 8Kadane's AlgorithmDrop the past the moment it starts costing you.6m