Best Time to Buy and Sell Stocks III

• Time : O(n)
• Space : O(n)

int Solution::maxProfit(const vector<int> &A) {
    if(A.size() < 2) return 0;
    vector<long long> dp(A.size() + 2, INT_MIN), dpp(A.size() + 2,INT_MIN);
    long long ma = A.back(), res = 0;
    for(int i = A.size() - 2; i >= 0; i--) {
        dp[i] = max(dp[i+1], ma - A[i]);
        dpp[i] = max(dpp[i + 1], dp[i+2] + A[i + 1]);
        ma = max(ma,1ll*A[i]);
        res = max(res, dpp[i] - A[i]);
    }
    return max(res,dp[0]);
}