Intialisation problem

when should i intialise my dp array with -1 and when with 0
sometimes -1 gives the right ans some times 0 …

it completely depend on question’s requirement

most of the time we are using 0 to initialise

what kind of questions? why cant the same problem if i intialise by 0

as i said it depend on question
sometime we have to initialise with i or 0 or 1