https://school.programmers.co.kr/learn/courses/30/lessons/42885
def solution(people, limit):
answer =0
people.sort() #작은수에서 큰수
left = 0
right = len(people)-1
while left <= right:
if people[left] + people[right] <= limit:
left += 1
right -= 1
else:
right -= 1
answer +=1
return answer