# 401.Binary Watch

**401.Binary Watch**

难度:Easy

> 二进制手表顶部有 4 个 LED 代表小时（0-11），底部的 6 个 LED 代表分钟（0-59）。

每个 LED 代表一个 0 或 1，最低位在右侧。

![](https://i.loli.net/2019/07/05/5d1f1622b8a3960150.jpg)

例如，上面的二进制手表读取 “3:25”。

给定一个非负整数 n 代表当前 LED 亮着的数量，返回所有可能的时间。

```
案例:

输入: n = 1
返回: ["1:00", "2:00", "4:00", "8:00", "0:01", "0:02", "0:04", "0:08", "0:16", "0:32"]
 

注意事项:

输出的顺序没有要求。
小时不会以零开头，比如 “01:00” 是不允许的，应为 “1:00”。
分钟必须由两位数组成，可能会以零开头，比如 “10:2” 是无效的，应为 “10:02”。
```

时钟一共四个选择，最多亮三盏灯；分钟一共六个选择，最多亮五盏灯。全部枚举出来即可。

```
class Solution {
    vector<vector<string>>H={{"0"}, {"1","2","4","8"}, {"3","5","6","9","10"}, {"7","11"}};
    vector<vector<string>>M={{"00"},{"01","02","04","08","16","32"},{"03","05","06","09","10","12", "17","18","20","24","33","34","36","40","48"},{"07","11","13","14","19","21","22","25","26","28","35","37","38","41","42","44","49","50","52","56"},{"15","23","27","29","30","39","43","45","46","51","53","54","57","58"},{"31","47","55","59"}};
    
public:
    vector<string> readBinaryWatch(int num) {
        vector<string>res;
        if(num>8) return res;

        for(int i=max(0,num-5);i<=min(num,3);i++)
                for(auto h:H[i])
                    for(auto m:M[num-i] )
                res.push_back(h+":"+m);
        return res;
    }
};
```

> 执行用时 :8 ms, 在所有 C++ 提交中击败了82.86%的用户\
> 内存消耗 :8.8MB, 在所有 C++ 提交中击败了44.21%的用户


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