Given an array of integers that may contain duplicates, ganerate all unique permutations of the array. This problem extends the classic permutation generation by requiring the elimination of duplicate sequences that arise from identical elements. Key Insight When elements repeat, naive backtracking...
Combination Sum III Find all valid combinations of k distinct numbers from 1 to 9 that sum to a target value n. A backtracking approach is used with two pruning strategies: Skip further exploration if the current sum exceeds n. Limit the loop range to ensure enough remaining numbers are available to...
Depth-first search (DFS) is characterized by advancing as far as possible along a single branch before retreating. This retreat occurs only upon encountering a dead end, which arises either from hitting a boundary or from reaching a previously visited location. Upon backtracking, the algorithm retur...