About the logic in the program

#1

Can this qstn solved using the technique used in harvesting rainwater problem or can that problem be solved using stack?

#2

Hey ,I dont think so it can be solved using that way .
If you have some approach in mind then tell me & I will tell you where it can fail.
And yes according to me the most optimized approach is using stacks only.

#3

Idea is like creating 2 arrays that will maintain the leftmost smallest element index and the other array maintaining the rightmost smallest element index .Thn from there we can calculate area

#4

Say array of prices is
100 80 60 70 60 75 85
then
Your first array will be
0 1 2 2 2 2 2
And second array will be
4 4 4 4 4 5 6
Now how will u proceed further?