题解 | #向下取整#

function _reverse(number) {
    // 补全代码
    let arr = String(number).split('');
    let l = 0;
    if(arr[0] === '-') l = 1;
    let r = arr.length - 1;
    if(arr.length === 1) return number;
    while(l <= r){
        [arr[r],arr[l]] = [arr[l],arr[r]];
        l++;
        r--;
    }
    return Number(arr.join(''));
}