##### Short Problem Definition:

There is an array of integers. There are also **2** **disjoint sets**, A and ,B each containing m integers. You like all the integers in set A and dislike all the integers in set B. Your initial happiness is 0. For each a integer in the array, if A, you add 1 to your happiness. If b in B, you add -1 to your happiness. Otherwise, your happiness does not change. Output your final happiness at the end.

##### Link

##### Complexity:

time complexity is `O(N)`

space complexity is `O(1)`

##### Execution:

Make sure that you convert A and B into sets to reduce the lookup times.

##### Solution:

```
def noIdea(N, A, B):
happiness = 0
A = set(A)
B = set(B)
for n in N:
if n in A:
happiness += 1
elif n in B:
happiness -= 1
return happiness
```