This code solves the https://codility.com/demo/take-sample-test/number_solitaire/ - DP - HARD

NumberSolitaire.cpp

#include <vector>
int solution(vector<int> &A) {
    
    vector<int> st(A.size() + 1);
    st[0] = A[0];
    int last_max = 0;
    
    for (size_t i = 1; i < A.size(); i++) {
        st[i] = max(st[i - 1], st[last_max]) + A[i];
        st[last_max] = max(st[last_max], st[i - 1]);
        
        if (i - last_max >= 6) {
            last_max++;
            for (int j = last_max + 1, k = last_max + 6; j < k; j++) {
                if (st[j] > st[last_max]) {
                    last_max = j;
                }
            }
        }
    }
    return st[A.size() - 1];
}