113th LeetCode Weekly Contest Reveal Cards In Increasing Order

Example 1:

Input: [17,13,11,2,3,5,7]
Output: [2,13,3,11,5,17,7]
Explanation: 
We get the deck in the order [17,13,11,2,3,5,7] (this order doesn‘t matter), and reorder it.
After reordering, the deck starts as [2,13,3,11,5,17,7], where 2 is the top of the deck.
We reveal 2, and move 13 to the bottom.  The deck is now [3,11,5,17,7,13].
We reveal 3, and move 11 to the bottom.  The deck is now [5,17,7,13,11].
We reveal 5, and move 17 to the bottom.  The deck is now [7,13,11,17].
We reveal 7, and move 13 to the bottom.  The deck is now [11,17,13].
We reveal 11, and move 17 to the bottom.  The deck is now [13,17].
We reveal 13, and move 17 to the bottom.  The deck is now [17].
We reveal 17.
Since all the cards revealed are in increasing order, the answer is correct.

class Solution {
public:
    vector<int> deckRevealedIncreasing(vector<int>& deck) {
        int s = deck.size();
        sort(deck.begin(),deck.end());
        if(s==1){
            return deck;
        }
        if(s==2){
            return deck;
        }
        vector<int> result;
        result.push_back(deck[s-2]);
        result.push_back(deck[s-1]);
        for(int i=s-3;i>=0;i--){
            
            
            int len = result.size();
            int last= result[len-1];
            result.insert(result.begin(),last);
            
            
            result.pop_back();
            result.insert(result.begin(),deck[i]);
            

        }
        return result;
    }
};