Interview Pattern Synthesis Python practice problems
Greedy proof, bit manipulation, and mixed-pattern practice that combines earlier techniques.
Core concepts
Problem-solving patterns
- greedy · array · LeetCode pattern
- greedy proof · array · company screen
- backtracking · combination sum · LeetCode pattern
- backtracking · grid
- hash set · matrix · LeetCode pattern
What this topic builds
Learn the idea once, use it across the exercises, and explain why your approach works.
All 12 problems in this topic
Work from top to bottom to build the concept gradually.
- #349Decide if the last array index is reachable: Reachable final indexBeginnerPremium
Determine whether some sequence of jumps reaches the last position.
- #350Decide if the last array index is reachable: Blocked by zeroBeginnerPremium
Return False when every route is trapped before the end.
- #351Find a valid gas-station start: One valid starting stationIntermediatePremium
Find a station from which one complete circuit is possible.
- #352Find a valid gas-station start: Impossible circuitIntermediatePremium
Return -1 when total fuel is less than total travel cost.
- #353Generate target-sum combinations: Two combination familiesIntermediatePremium
List every nondecreasing candidate combination that reaches the target.
- #354Generate target-sum combinations: No combinationIntermediatePremium
Report None when the target cannot be built from the candidates.
- #355Search a word in a character board: Word existsIntermediatePremium
Determine that adjacent cells can spell the target without reusing a cell.
- #356Search a word in a character board: Reuse would be requiredAdvancedPremium
Return False when spelling the target would need the same board cell twice.
- #357Validate a Sudoku board: Valid partial boardAdvancedPremium
Validate a partially filled board with no repeated constrained digits.
- #358Validate a Sudoku board: Invalid duplicateAdvancedPremium
Detect a repeated digit inside the top-left 3-by-3 box.
- #359Find the single value with XOR: Unpaired positive valueAdvancedPremium
Find the only value without a duplicate.
- #360Find the single value with XOR: Negative single valueAdvancedPremium
The XOR method also works with Python's signed integers.