Leetcode 1423. The maximum number of points available

1 Title Description （Leetcode Topic link ）

How many cards Line up , Each card has a corresponding number of points . The number of points is an array of integers cardPoints give .

Every action , You can take a card from the beginning or the end of the line , In the end, you have to just take k Cards .

Your number of points is the sum of the number of points you get from all the cards in your hand .

Give you an array of integers cardPoints And integer k, Please return the maximum number of points you can get .

 Input ：cardPoints = [1,2,3,4,5,6,1], k = 3
 Output ：12
 explain ： For the first time , No matter which card you take , Your points are always  1 . however , Taking the card on the far right first will maximize your points . The best strategy is to take the three cards on the right , The final point is  1 + 6 + 5 = 12 .

2 Answer key

With k = 3 For example , Just traverse like the following figure

python

class Solution:
    def maxScore(self, cardPoints: List[int], k: int) -> int:
        temp = sum(cardPoints[:k])
        res = temp
        n = len(cardPoints)
        i = 1
        while i <= k:
            temp = temp - cardPoints[k - i] + cardPoints[n-i]
            res = max(res, temp)
            i += 1
        return res

C++

class Solution {
    
public:
    int maxScore(vector<int>& cardPoints, int k) {
    
        int temp = 0, n = cardPoints.size();
        for(int i=0; i<k; i++){
    
            temp += cardPoints[i];
        }
        int res = temp, i = 1;
        while(i <= k){
    
            temp = temp - cardPoints[k-i] + cardPoints[n-i++];
            res = max(res, temp);
        }
        return res;
    }
};