End-to-end encryption and privacy controls.
Message and call for free* around the world.
Group conversations made simple.
Say it with stickers, voice, GIFs and more.
Reach your customers from anywhere.
Java 예제: 로또 (중복없이 배열에서 값 추출, 배열 원소 스왑) + HashSet 이용 http://yoonbumtae.com/?p=628