Problem Link

Can anyone please explain how to solve this question by DP.

I have read the tutorial of this problem but still can't get the intuition.

Or please suggest similar question question to get the intuition.

can anyone give idea , how to solve question 4 in order of time complexity N , atcoder beginner contest 159. Link: https://atcoder.jp/contests/abc159/tasks/abc159_d

Here is my code for Problem C, https://atcoder.jp/contests/abc158/submissions/10762664

Please , can anyone help me one this...

All helps are appreciated. Thank you :)

Hey!!! i am solving problem in codeforces since last month and in codechef since a year. I am solve to solve 2 to 3 questions in codechef and codeforces in every contest. I observe starting 1 to 2 questions are maths in codeforces and 1 to 4 questions in codechef are based on mathematics... I am always get stuck in question number 3 in codechef and codeforces... I need help and suggestion what are the mathematics topics i should read and how can i improve my skills from this level... Thank you !!!