runtime/collection.c에 추가:\\n- sort(vec), reverse(vec)\\n- flatten(vec), distinct(vec)\\n- take(n,vec), drop(n,vec)\\n- zip(a,b), partition(n,vec), interpose(sep,vec)\\n- group_by(fn,vec), frequencies(vec)\\n- keys(map), vals(map), entries(map)\\n- dissoc(map,key), select_keys(map,keys)\\n- min(a,b...), max(a,b...)\\n\\n통과: gcc -Wall -Wextra 경고 0, 각 함수 출력 검증