Leetcode Back Tracking Problems
Back tracking is the common approach to solve problems about combinations, subsets, permutations or all possible solutions. When asked optimize result or max/min values, we should consider dynamic programming approach first as it usually has better time complexity. The time complexity of back tracking problem are various. For example, Hamiltonian cycle: O(N!), WordBreak: O(2^N) and NQueens: O(N!).