技術標籤：LeetCode基礎演算法/思維

Description

Solution
最終的方案一定是字首+字尾，故 O ( N ) O(N) O(N)字首和列舉即可

Code

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

};