首页 > 代码库 > Well-ordered String

Well-ordered String

2024-08-03 12:05:45   218人阅读

Problem

You know a password is well-ordered string. Well-ordered string means that the order of the characters is in an alphabetical increasing order. Like “abEm” is a well-ordered number. However, “abmE” is not a well-order number. Given an input# that tells you also how many digits are in the password, print all possible 

Solution

Recursive + DFS

 1     public static List<List<String>> hackCode(int num) { 2         List<List<String>> res = new ArrayList<List<String>>(); 3         if (num < 0) { 4             return res; 5         } 6  7         List<String> ls = new ArrayList<String>(); 8         helper(res, ls, 0, num, 0); 9         return res;10     }11 12     public static void helper(List<List<String>> res, List<String> ls, int prev,13             int num, int pos) {14         if (pos == num) {15             res.add(new ArrayList<String>(ls));16             return;17         }18 19         for (int i = prev; i < 26; i++) {20             char c = (char) (‘a‘ + i);21             ls.add(String.valueOf(c));22             helper(res, ls, i + 1, num, pos + 1);23             ls.remove(ls.size() - 1);24         }25     }

 

Well-ordered String


联系
我们