头条2020届实习生笔试题

    // 判断是否为闰年
    function isRun(a) {
        return a % 4 == 0 && a % 100 != 0 || a % 400 == 0
    }

    // 判断是这一年的第几天
    function daysNum(year,month,day) {
        var months = [31,28,31,30,31,30,31,31,30,31,30,31];
        if(month ==1)  {
            return day;
        }
        for(var i = 0; i < month-1; i++) {
            day += months[i]
        }
        if(isRun(year) && month >2) {
            day ++
        }
        return day
    }

    function SelectNum(arr) {
        let len = arr.length;
        var json = {};
        for (let i = 0; i < len; i++) {
            if (json[arr[i]] == undefined) {
                json[arr[i]] = 1;
            } else {
                json[arr[i]] += 1
            }
        }
        for (let a in json) {
            if (json[a] > len / 2) {
                return a
            }
        }

        return ‘没有元素占大多数‘
    }