leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
Log | Files | Refs | README | LICENSE

1286.cpp (743B)

      1 class Solution {
      2     vector<int> vec;
      3     const string chars;
      4     string res;
      5 
      6     bool has_next = true;
      7     void shuffle() {
      8         int goal = chars.size() - 1, idx = vec.size() - 1;
      9         while (idx > 0 && vec[idx] == goal)
     10             goal--, idx--;
     11         for (int i = idx, acc = vec[idx]; i < vec.size(); i++)
     12             res[i] = chars[vec[i] = ++acc];
     13         if (idx == 0 && vec[0] == goal) has_next = false;
     14     }
     15 
     16   public:
     17     CombinationIterator(string chars, int len) : chars(chars), vec(len), res(len, ' ') {
     18         for (int i = 0; i < len; i++)
     19             res[i] = chars[vec[i] = i];
     20         vec.back()--;
     21     }
     22 
     23     string next() {
     24         shuffle();
     25         return res;
     26     }
     27 
     28     bool hasNext() { return has_next; }
     29 };