https://school.programmers.co.kr/learn/courses/30/lessons/12987
def solution(A, B):
A.sort()
B.sort()
count = 0
ptA=0
ptB=0
while ptA < len(A) and ptB < len(B) :
if A[ptA] < B[ptB] :
ptA += 1
ptB += 1
count +=1
else :
ptB += 1
return count
# 정렬 후 포인터 이동
# 1 3 5 7
#
# 2 2 6 8