Description

Submission

class Solution {
    int dp[2][40005];   // max til now(continuously)
public:
    int maxTurbulenceSize(vector<int>& arr) {
        dp[0][0] = dp[1][0] = 1;
        for(int i = 1; i < arr.size(); ++i) {

            if(i % 2 == 1) {    // if k is odd
                if(arr[i-1] < arr[i]) {
                    dp[0][i] = dp[0][i-1] + 1;
                } else {
                    dp[0][i] = 1;
                }
                if(arr[i-1] > arr[i]) {
                    dp[1][i] = dp[1][i-1] + 1;
                } else {
                    dp[1][i] = 1;
                }
            } else {
                if(arr[i-1] < arr[i]) {
                    dp[1][i] = dp[1][i-1] + 1;
                } else {
                    dp[1][i] = 1;
                }
                if(arr[i-1] > arr[i]) {
                    dp[0][i] = dp[0][i-1] + 1;
                } else {
                    dp[0][i] = 1;
                }
            }
        }

        int ret = 0;
        for(int i = 0; i < 2; ++i) {
            for(int j = 0; j < arr.size(); ++j) {
                ret = max(ret, dp[i][j]);
                // cout << dp[i][j] << " ";
            }
            // cout << endl;
        }
        return ret;
    }
};