1 class Solution
 2 {
 3     public:
 4         vector<int> deckRevealedIncreasing(vector<int>& deck)
 5         {
 6             sort(deck.begin(),deck.end());
 7             vector<int> rnt (deck.size(),0);
 8             int deckend = 0;
 9             int flag = 1;
 
10             for(int i = 0;deckend < deck.size();i = (i+1)%(deck.size()))
11             {
12                 if(!rnt[i])
13                 {
14                     if(flag) rnt[i] = deck[deckend++];
15                     flag = !flag;
16                 }
17             }
18             return
 
 rnt;
19         }
20 };

參考了大神的程式碼，本質是約瑟夫環。在還沒填上數字的空格里隔一個填一個