import sys
input=sys.stdin.readline
n,m=map(int, input().split())
arr=set()
arr2=set()
for _ in range(n):
arr.add(input().rstrip())
for _ in range(m):
arr2.add(input().rstrip())
res=sorted(list(arr & arr2))
print(len(res))
for i in res:
print(i)
import sys
input=sys.stdin.readline
n,m=map(int, input().split())
arr=set()
res=[]
for _ in range(n):
s=input().rstrip()
arr.add(s)
for _ in range(m):
s=input().rstrip()
if s in arr:
res.append(s)
print(len(res))
res.sort()
print(*res, sep="\n")
1
import sys
input = sys.stdin.readline
N, M = map(int, input().split())
n = {input().strip() for _ in range(N)}
m = {input().strip() for _ in range(M)}
nm = sorted(n&m)
print(len(nm), *nm, sep='\n')
2
import sys
input = sys.stdin.readline
n, m = map(int, input().split())
arr1 = dict()
answer = []
for i in range(n):
x = input()
if x not in arr1:
arr1[x] = i
for i in range(m):
y = input()
if y in arr1:
answer.append(y)
answer.sort()
print(len(answer))
print(''.join(answer), end = '')
- set
선언 : arr=set()
값 추가 : arr.add
값 삭제 : arr.remove
교집합 : a & b
합집합 : a | b
차집합 : a - b