Help with error

#1

code: https://ide.codingblocks.com/s/422967 2

prob: https://hack.codingblocks.com/app/contests/2022/243/problem 2

I referred to this video and tried to implement their solution

#2

which video you are refering?

what is your approach to solve this problem

#3

this one
#4

the approach you have tried is not correct
you are adding head->data of both the list

suppose lists are
1 2 3
6 7 8 9 4

you are adding 1 and 6 which is wrong
you have to add 4 with 3, 1 with 8
like normal addtion

Correct approach