十亿手机号去重-BitSet

思路：使用Java自带BitSet函数，将手机号分为两段（15555555555 -> 155+55555555）

public class demo {
    public static void main(String[] args) {
        Map<Integer, BitSet> map = new HashMap<>(20);
        long[] phone = {15522222222L, 15533333333L, 15544444444L, 15522222222L};

        for (int i = 0; i < phone.length; i++) {
            int num0 = (int) (phone[0] / 100000000);
            int num1 = (int) (phone[i] % 100000000);
            map.computeIfAbsent(num0, k -> new BitSet());
            map.get(num0).set(num1);
        }

        for (int i = 0; i < 999999999; i++) {
            if (map.get(155).get(i)) {
                System.out.println("155" + i);
            }
        }
    }
}

截图：