题解 | #整数与IP地址间的转换#

let input;
let lineNum = 1;
while (input = readline()) {
    if (lineNum === 1) {
        let arr = input.split('.');
        let newArr = [];
        for (let i = 0; i < arr.length; i++) {
            let item = parseInt(arr[i]).toString(2).split('');
            const len = item.length;
            for (let j = 0; j < 8 - len; j++) {
                item.unshift('0');
            }
            newArr.push(item.join(''));
        }
        print(parseInt(newArr.join(''), 2));
    }
    
    if (lineNum === 2) {
        let str = parseInt(input).toString(2);
        const len = str.length;
        let newArr = [];
        for (let i = 0; i < 4; i++) {
            let index = len - 8 * (i+1);
            if (i === 3) {
                index = 0;
            }
            const item = str.slice(index, len - 8 * i);
            newArr.unshift(parseInt(item, 2));
        }
        
        print(newArr.join('.'));
        
        lineNum = 0;
    }
    
    lineNum++;
}