MediumHigh Frequency40 min
0/1 Knapsack & Unbounded Knapsack
The most important DP sub-category — choose items with weight/value constraints.
0/1 knapsack: each item used once. dp[i][w]=max value using items 0..i with capacity w. Include/exclude choice. Unbounded: item reusable. Subset sum: can you reach target weight?