题解 | #简单密码#

思路比较简单，主要就是if的使用，String.fromCharCode()和str.charCodeAt()方法对unicod和字符之间的转换，toLowerCase()方法将大写字母改小写，join方法将数组中的逗号去掉

let input = readline()
var str = input.split('')
for(var i=0 ; i<input.length ; i++){        //直接将输入的字符串转成数组进入循环遍历
    if( str[i] >= 'a' && str[i] <= 'c' )        //如果是小写字母，按手机九键的规则进行转换
        str[i] = 2                              //这里使用if判断，比较简单明了
    else if( str[i] >= 'd' && str[i] <= 'f' )
        str[i] = 3
    else if( str[i] >= 'g' && str[i] <= 'i' )
        str[i] = 4
    else if( str[i] >= 'j' && str[i] <= 'l' )
        str[i] = 5
    else if( str[i] >= 'm' && str[i] <= 'o' )
        str[i] = 6
    else if( str[i] >= 'p' && str[i] <= 's' )
        str[i] = 7
    else if( str[i] >= 't' && str[i] <= 'v' )
        str[i] = 8
    else if( str[i] >= 'w' && str[i] <= 'z' )
        str[i] = 9
    if( str[i] >= 'A'  &&  str[i] < 'Z' )       //使用toLowerCase()方法将大写字母改小写
        str[i] = String.fromCharCode(str[i].charCodeAt(0)+1).toLowerCase()    //String.fromCharCode()和str.charCodeAt()方法对unicod和字符之间的转换
    if(str[i] == 'Z')
        str[i] = 'a'
}
console.log(str.join(''))    //join方法将数组中的逗号去掉