DSA

Classic DP Problems

Master the most common dynamic programming patterns: Knapsack, LCS, and more.

By TechCoder TeamLast updated: 2026-06-02
In a Nutshell

Master the most common dynamic programming patterns: Knapsack, LCS, and more. This hands-on tutorial focuses on practical implementation of classic dp problems concepts.

Classic DP Problems

Now that you understand the core concepts of memoization and tabulation, let's apply them to problems that are frequently asked in top-tier interviews.

1. 0/1 Knapsack Problem

Given weights and values of $n$ items, put these items in a knapsack of capacity $W$ to get the maximum total value. You cannot break items (0/1).

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2. Longest Common Subsequence (LCS)

Find the length of the longest subsequence present in both strings.

  • Example: "abcde" and "ace" -> "ace" (Length 3)
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Pattern Comparison: Knapsack vs LCS

ProblemDimensionSpace ComplexityCore Logic
Knapsack2D (Items x Weight)O(W) optimizedTaking vs Leaving
LCS2D (String1 x String2)O(min(m,n)) optimizedMatch vs Mismatch

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Quiz

Quiz

Question 1 of 2

In the 0/1 Knapsack problem, why can't we use a greedy approach based on value/weight ratio?

Because items are invisible
Because we cannot take fractions of an item
Because greedy is always slower
Because the ratio is always constant