Leetcode978. Longest Turbulent Subarray

给定一个数组，找到最长的turbulent子数组的长度

turbulent子数组就是一增一减交替

其实这题也很简单，就是直接找子数组，不满足条件了，就重新开始算

class Solution {
public:
    int maxTurbulenceSize(vector<int>& arr) {
        int ans = 1, n = arr.size(), cur = 1;
        int state = 0;
        for(int i = 1; i < n; ++i){
            if(arr[i] == arr[i - 1]){
                state = 0;
                cur = 1;
            }
            else if(arr[i - 1] < arr[i]){
                if(state == -1){
                    ++cur;
                }
                else{
                    cur = 2;
                }
                ans = max(cur, ans);
                state = 1;
            }
            else{
                if(state == 1){
                    ++cur;
                }
                else{
                    cur = 2;
                }
                ans = max(cur, ans);
                state = -1;
            }
        }
        return ans;
    }
};
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时间复杂度$O(n)$