Divide & Conquer Dynamic Programming Optimisation, CSES Subarray Squares

CSES Subarray Squares: https://cses.fi/problemset/task/2086 My code: https://cses.fi/paste/868eebff0bc435411acbce/ Convex Hull Trick tutorial: https://www.youtube.com/watch?v=HnZKQJtGeHs Quadrangle Inequality Insights: https://codeforces.com/blog/entry/86306 CP-Algorithms D&C DP tutorial: https://cp-algorithms.com/dynamic_programming/divide-and-conquer-dp.html Practice problem: https://codeforces.com/contest/321/problem/E