problem:2024. 考试的最大困扰度

思路：T和F各求一遍滑动窗口维护不超过k个相异字符

Accode:

class Solution {
public:
    int toggle(string answerKey,char c,int k){
        int ans = 0;
        // int len = answerKey.length();
        deque<char> deq;
        int tot = 0;
        for(auto it:answerKey){
            while(deq.size() && tot>=k && it==c){
                if(deq.front()==c) tot--;
                deq.pop_front();
            }
            deq.push_back(it);
            if(it==c) tot++;
            ans = max(ans,(int)deq.size());
        }
        return ans;
    }
    int maxConsecutiveAnswers(string answerKey, int k) {
        return max(toggle(answerKey,'T',k),toggle(answerKey,'F',k));
    }
};

时间复杂度：$o(n)$