A+
Basic
0 / 9S+
Advanced
0 / 1017Letter Combinations of a Phone NumberBacktracking79Word SearchDFS + Backtracking131Palindrome PartitioningPartition698Partition to K Equal Sum SubsetsBitmask + pruning (in main Backtracking)51N-QueensBacktracking classic37Sudoku SolverBacktracking classic140Word Break IIBacktracking + memoization301Remove Invalid ParenthesesBacktracking + pruning282Expression Add OperatorsBacktracking + computation489Robot Room CleanerBacktracking + simulation