Method equals

java/0920-number-of-music-playlists.java:45–51

(Object obj)

        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) return true;
            if (obj == null || getClass() != obj.getClass()) return false;
            Pair pair = (Pair) obj;
            return a == pair.a && b == pair.b;
        }

        @Override
        public int hashCode() {