https://leetcode.com/problems/binary-watch/
題目的大致意思是這樣的：
首先介紹一下Binary Watch
表盤(pán)上10個(gè)燈，開(kāi)和關(guān)分別代表1和0.
前4個(gè)燈表示小時(shí)，后6個(gè)燈表示分鐘數(shù)。
現(xiàn)在給出亮的燈數(shù)n,求出可以表示的時(shí)間。
直接上代碼

先來(lái)一份C++的代碼

class Solution {
public:
    vector<string> readBinaryWatch(int num) {
        vector<string> res;
        for(int h=0; h<12; h++)
        for(int m=0; m<60; m++)
            if (bitset<10>(h<<6|m).count() == num)
                res.push_back(to_string(h)+(m<10?":0":":")+to_string(m));
        return res;
        
    }
};

接著我又用swift 重寫(xiě)了，由于沒(méi)有找到swift的bitset類，所以直接枚舉出了所有的時(shí)鐘和分鐘數(shù)字。

class Solution {
    func readBinaryWatch(_ num: Int) -> [String] {
        var hour:[[String]] = [["0"],["1","2","4","8"],["3","5","6","9","10"],["7","11"]]
        var minute:[[String]] = [["00"], //1
            ["01", "02", "04", "08", "16", "32"], //6
            ["03", "05", "06", "09", "10", "12", "17", "18", "20", "24", "33", "34", "36", "40", "48"], //15
            ["07", "11", "13", "14", "19", "21", "22", "25", "26", "28", "35", "37", "38", "41", "42", "44", "49", "50", "52", "56"], //20
            ["15", "23", "27", "29", "30", "39", "43", "45", "46", "51", "53", "54", "57", "58"], //14
            ["31", "47", "55", "59"]]
        var res:[String] = [String]()
        for i in 0...3 {
            for j in 0...5 {
                if(i + j == num) {
                    for str1 in hour[i] {
                        for str2 in minute[j] {
                            res.append(str1+":"+str2)
                        }
                    }
                }
            }
        }
        return res
    }
}