I tried solving a different question of this same type where we are told to calculate the total nmber of ways to form a total using a coins array…what is going wrong in my code plz correct it

# Coin Change Problem

at line no 24

correct statement will be

int subproblem = solve(arr, n - arr[i], m)+1;

you also have to add 1

Still getting wrong answer…answer should be 4 i am getting 14

for which input you are trying?

N=4

arr={1,2,3}

this is my input

POssible ways can be 1111 22 13 112

This question is just a variation of the question shown in videos right so the logic is correct no?

actually the problem is

first you set dp[0]=1 and then you use menset to set all values=0

so dp[0]=1 should be used later

I made some changes…but no luck…

this will not work

previous one is better

but there is also problem with that

it is considering the reduntant case also

for example for n=4

it is considering

1 1 1 1

1 1 2

1 2 1

1 3

2 1 1

2 2

3 1

as you can see there is repetation

so this approach is not correct

this is correct way to do this

using memoization

you have to make 2D array

I am a bit confused about how to decide m and n as column or row if i would have taken n as columns and m as rows would the answer differ?

Can u please explain ur intuition for choosing rows and columns

no there will be no problem

why should ans differ?

you are storing the ans of m,n at dp[m][n] and using it when required

if you use dp[n][m] then also you can use it

okay understood Thank you

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