题解 | #字符串合并处理#

while(line = readline()) {
var s = line.replace(/\s/g, '');
var a = [];
var b = [];
for (var i = 0; i< s.length; i++) {
if (i % 2 == 0) {
a.push(s[i]);
} else {
b.push(s[i]);
}
}
a.sort();
b.sort();
var r = [];
for (var i = 0; i < a.length; i++) {
a[i] && r.push(a[i]);
b[i] && r.push(b[i]);
}
var result = r.map((item) => {
return enCode(item);
})
console.log(result.join(''));
}

function enCode(s) {
var reg = new RegExp(/\d|[a-f]/gi);
if (reg.test(s)) {
var nE = (('0000' + parseInt(s, 16).toString(2))).slice(-4).split('').reverse().join('');
var char = (parseInt(nE, 2)).toString(16).toUpperCase();
return char;
} else {
return s;
}
}