LeetCode: Best Time to Buy and Sell Stock III

class Solution {
public:
    const int inf = 1e9;

    int dp[100010][5];
    int mx[100010][5];

    int maxProfit(vector<int>& prices) {
        int n = prices.size();
        for(int i=n-1;i>=0;i--){
            dp[i][1] = max(dp[i+1][1], - prices[i] + mx[i+1][0]);
            dp[i][2] = max(dp[i+1][2], - prices[i] + mx[i+1][1]);
            mx[i][0] = max(mx[i+1][0], prices[i] + dp[i+1][0]);
            mx[i][1] = max(mx[i+1][1], prices[i] + dp[i+1][1]);
        }

        return max(dp[0][1], dp[0][2]);
    }
};