Perfectly running code giving run error

#1


This code is running perfectly everywhere but gives run error on submission

#2

@Garvit012,
n is too big to be made an array of. 1e9 * 4 Bytes =~ 3.5 GB.

#3

then what should I do?

#4

@Garvit012,
You should do it top down recursively, with map for memoization.