• Word Search T: O(n * m * 4^n)
• Letter Case Permutation T: O(M * 2^L)
• Subsets T: O(2^n)
• Subsets-II T: O(n.2^n)
• Permutations T: O(2^n)
• Permutations II T: O(n.2^n)
• Combinations T: O(k.n^k)
• Combination Sum - T: O(2^T) where T will be our target
• Combination Sum II - T: O(2^n) where n will be our target or height of the tree
• Combination Sum III T: O(2^n)
• Generate Parentheses T: O(2^n)
• Palindrome Partitioning ****T: O(2^n)
• Letter Combinations of a Phone Number T: O(n.4^n)
• Generalized Abbreviation T: O(n.2^n)
• Sudoku Solver(Later)
• N-Queens T:O(n!)