Best Time to Buy and Sell Stock atmost B times

• Time : $O(n * min(n,B))$
• Space : $O(n)$

c++

int Solution::solve(vector<int> &A, int B) {
    int n = A.size(), res = 0;
    vector<int> dp(n + 1);
    for(int i = 0; i < min(n,B); i++) {
        vector<int> dpp(n + 1);
        int ma = 0;
        for(int j = n - 1; j >= 0; j--) {
            dpp[j] = max({dp[j], ma - A[j], dpp[j+1]});
            ma = max(ma, dp[j + 1] + A[j]);
            res = max(res, dpp[j]);
        }
        swap(dp,dpp);
    }
    return res;
}