Method ipToLong

java/751_IP_to_CIDR.java:14–20

(String ip)

        return ans;
    }
    private long ipToLong(String ip) {
        long ans = 0;
        for (String x: ip.split("\\.")) {
            ans = 256 * ans + Integer.valueOf(x);
        }
        return ans;
    }
    private String longToIP(long x) {
        return String.format("%s.%s.%s.%s",
            x >> 24, (x >> 16) % 256, (x >> 8) % 256, x % 256);