RationalDeveloper's blog

By RationalDeveloper, history, 3 months ago, In English

I have trying to solve a lot of DP problem but I feel stuck. I can solve most of greedy problem. Any advice

 
 
 
 
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3 months ago, # |
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If you are beginner in DP , I would suggest you practice Recursive DP first. Almost all DP problems you see until 1700-1800 rating can be easily solved with recursive version.

Still if you want to learn iterative, I think writing the transitions on paper helps a lot.

For example, Suppose recursive version is,
inside func(i,j):
DP[i][j] = func(i+1,j+1) + func(i+2,j+1);

I generally convert that right most term into i... like

DP[i-2][j-1] = func(i-1,j) + func(i,j);
=> DP[i-2][j-1] = DP[i-1][j] + DP[i][j]
=> DP[i][j] = DP[i-2][j-1] -DP[i-1][j]

Now I have a formula to use iterative dp using for loop.

PS:This is just personal opinion. There may be better way to figure out transitions. But I learnt it this way. :P

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    3 months ago, # ^ |
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    thank you so much for replying. really appreciate. I will try them in recursion.Before I was only trying iterative.

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      3 months ago, # ^ |
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      Add Ashishgup to your friendlist and refer his solutions for problems you are trying to solve. He almost always solves using recursive and you can see his solutions to learn.