Master the art of solving complex problems by breaking them into simpler subproblems. Learn memoization, tabulation, and optimization techniques for efficient algorithms.
Optimal solution can be constructed from optimal solutions of subproblems
Same subproblems are solved multiple times in naive recursive approach
Store and reuse results of expensive function calls for efficiency
Problems with 1D state space
Problems with 2D state space
Problems on ranges or intervals
DP on tree structures
Recursive approach with caching of results
Complex state transitions, when not all subproblems needed
Iterative approach building solutions from base cases
When all subproblems are needed, space optimization important
Use only current and previous rows instead of entire 2D table
Example: 2D DP → O(2 × n) space
Use bit manipulation to represent states compactly
Example: Subset problems with bitmask
Map large coordinate space to smaller space
Example: Large range → array indices
Look for optimal substructure and overlapping subproblems
What parameters uniquely identify a subproblem?
Express solution in terms of smaller subproblems
Choose memoization or tabulation, optimize space
Practice with interactive visualizations and step-by-step solutions