Greedy video daught

#1

in coin change code

int idx=upper_bound(coins,coins+n,money)-1-coins;

why we are subtracting coins for getting index of coins which is just smaller than target

it is giving negative index

#2

Hi @hunt
we are subtracting coins to get index as upperbound returns a pointer at the index so we subtract coins from the pointer to get an int value of index.
i dont think the code will give -ive index since minvalue of money is 1 and we have coin with value 1 so upperboung of 1 will always give 1(index) and idx=upper_bound(coins,coins+n,money)-1-coins dis will give idx=0
still u can share ur code so that i can see where r u facing problem
hope dis helps