< Back ~ Problems ~ 46. Permutations ~ 78. Subsets ~ 77. Combinations ~ 797. All Paths From Source to Target ~ 17. Letter Combinations of a Phone Number ~ 39. Combination Sum ~ 52. N-Queens II ~ 22. Generate Parentheses ~ 967. Numbers With Same Consecutive Differences ~ 216. Combinations Sum III ~ 47. Permutations II ~ 40. Combination Sum II ~ 2305. Fair Distribution of Cookies ~ 1415. The k-th Lexicographical String of All Happy Strings of Length n ~ 491. Non-decreasing Subsequences ~ 93. Restore IP Addresses ~ 131. Palindrome Partitioning ~ 980. Unique Paths III ~ 37. Sudoku Solver