Backtracking
Explore decision trees depth-first, undo dead ends.
Constraint placement
Place items subject to constraints, backtracking on conflicts.
- N-Queens (Hard)
Enumeration
Generate every combination by including/excluding each choice.
- Subsets (Medium)
Checkpoint
A graded check — pass to certify the Backtracking topic.
Reference problems
18 imported reference solutions
- Combinations (Medium)
- All Length-K Strings from a Character Set (Easy)
- Combination Sum II (Medium)
- Decode Numbers (Hard)
- Expression Add Operators (Hard)
- Generate Binary Strings (Easy)
- Strobogrammatic Number II (Medium)
- Generate Parentheses (Medium)
- Letter Combinations of a Phone Number (Medium)
- Maximum Length of a Concatenated String with Unique Characters (Medium)
- Nested List Weight Sum (Easy)
- Different Ways to Add Parentheses (Medium)
- Restore IP Addresses (Medium)
- Permutations (Medium)
- Cartesian Product of Multiple Arrays (Medium)
- Permutations (string) (Medium)
- Word Search (Medium)
- Word Search II (Hard)
Pattern Quest
Practice recognizing backtracking problem shapes.