TRT - Treats for the Cows
FJ has purchased N (1 <= N <= 2000) yummy treats for the cows who get money for giving vast amounts of milk. FJ sells one treat per day and wants to maximize the money he receives over a given period time. The treats are interesting for many reasons:
- The treats are numbered 1..N and stored sequentially in single file in a long box that is open at both ends. On any day, FJ can retrieve one treat from either end of his stash of treats.
- Like fine wines and delicious cheeses, the treats improve with age and command greater prices.
- The treats are not uniform: some are better and have higher intrinsic value. Treat i has value v(i) (1 <= v(i) <= 1000).
- Cows pay more for treats that have aged longer: a cow will pay v(i)*a for a treat of age a.
Given the values v(i) of each of the treats lined up in order of the index i in their box, what is the greatest value FJ can receive for them if he orders their sale optimally?
The first treat is sold on day 1 and has age a=1. Each subsequent day increases the age by 1.
Line 1: A single integer, N
Lines 2..N+1: Line i+1 contains the value of treat v(i)
The maximum revenue FJ can achieve by selling the treats
Input: 5 1 3 1 5 2 Output: 43
I must admit I got the dreaded CE when I submitted my first solution that I cranked out without thinking much of the approach. Mind is blown after realising how sub-optimally I was thinking as well as the simplicity of it all. Nice problem indeed.
This is a popular DP question but the scenario known as "LINE OF WINE"
Nice Question for DP beginners, AC in one GO!
Refer to this - ( https://www.quora.com/Are-there-any-good-resources-or-tutorials-for-dynamic-programming-DP-besides-the-TopCoder-tutorial/answer/Michal-Danilák ) if you are having trouble.
Last edit: 2019-01-11 07:42:58
my code runs up to 11 then it shows wrong answer,help me out?
feeling i just got is awesome :))))))Last edit: 2018-10-29 14:40:54
There are two things of significance in this problem. First, find a way to represent age in terms of start and end indices so that you don't need it during memoization. Second, something very subtle, using unordered_map gave me TLE, switched to a 2D vector and it passed probably because finding if a key exists is not constant time in all cases whereas if you initialise a 2D vector with dummy values, checking if the key exists is a constant time operation.
For Newbies out there, I've written a very detailed editorial for this. Check it out