题解 | #整数与IP地址间的转换#

    pub fn huawei_2016_6() {
        fn binary_to_decimal(num: &str) -> Option<i64> {
            if num.len() == 0 {
                return None;
            }
            let mut sum = 0;
            let vec = num
                .chars()
                .map(|x| i64::from(x.to_digit(10).unwrap()))
                .collect::<Vec<i64>>();
            for (index, item) in vec.iter().rev().enumerate() {
                sum += i64::pow(2, index as u32) * item;
            }
            Some(sum)
        }
        pub fn input_vec_num<T>(split_by: &str) -> Vec<T>
        where
            <T as std::str::FromStr>::Err: std::fmt::Debug,
            T: std::str::FromStr,
        {
            let mut input = String::new();
            std::io::stdin().read_line(&mut input).unwrap();
            input
                .split(split_by)
                .filter(|s| !s.is_empty())
                .map(|s| s.trim().to_string())
                .map(|s| s.parse::<T>().unwrap())
                .collect::<Vec<T>>()
        }
        pub fn input_num<T>() -> T
        where
            <T as std::str::FromStr>::Err: std::fmt::Debug,
            T: std::str::FromStr,
        {
            let mut input = String::new();
            std::io::stdin().read_line(&mut input).unwrap();
            input.trim().to_string().parse::<T>().unwrap()
        }
        fn ip_to_int() {
            let ip = input_vec_num::<i64>(".");
            let mut ipb = String::new();
            for i in ip.iter() {
                let s = format!("{:8b}", i).replace(" ", "0");
                ipb.push_str(&s);
            }
            println!("{}", binary_to_decimal(&ipb).unwrap());
        }
        fn int_to_ip() {
            let num = input_num::<i64>();
            let s = format!("{:>032b}", num);
            let mut s_vec = vec![];
            for i in (0..s.len()).step_by(8) {
                s_vec.push(binary_to_decimal(&s[i..i + 8]).unwrap().to_string());
            }
            println!("{}", s_vec.join("."));
        }
        ip_to_int();
        int_to_ip();
    }
    fn main(){
        huawei_2016_6();
    }

`