978. Longest Turbulent Subarray

Link

Solution

紀錄上一個wave的狀態 (up/down/even)。

然後比較這次狀態，並進行count的變化

    public int maxTurbulenceSize(int[] A) {
        if(A.length <= 1) return A.length;
        int flag = 0; // 0: equal, 1 : up, -1 : down
        int count = 1;
        int max = 1;
        for(int i = 1; i < A.length; i++){
            if(A[i] > A[i-1]){
                if(flag == -1){
                    count++;
                }
                else{
                    count = 2;
                }        
                flag = 1;
            }
            else if (A[i] < A[i-1]){
                if(flag == 1){
                    count++;
                }
                else{
                    count = 2;
                }   
                flag = -1;
            }
            else{
                flag = 0;
                count = 1;
            }
            max = Math.max(max, count);
        }
        return max;
    }