闯关leetcode——3280. Convert Date to Binary

题目

地址

https://leetcode.com/problems/convert-date-to-binary/description/

内容

You are given a string date representing a Gregorian calendar date in the yyyy-mm-dd format.

date can be written in its binary representation obtained by converting year, month, and day to their binary representations without any leading zeroes and writing them down in year-month-day format.

Return the binary representation of date.

Example 1:

Input: date = “2080-02-29”
Output: “100000100000-10-11101”
Explanation:
100000100000, 10, and 11101 are the binary representations of 2080, 02, and 29 respectively.

Example 2:

Input: date = “1900-01-01”
Output: “11101101100-1-1”
Explanation:
11101101100, 1, and 1 are the binary representations of 1900, 1, and 1 respectively.

Constraints:

• date.length == 10
• date[4] == date[7] == ‘-’, and all other date[i]'s are digits.
• The input is generated such that date represents a valid Gregorian calendar date between Jan 1st, 1900 and Dec 31st, 2100 (both inclusive).

解题

这题就是要将一个10进制表示的日期类型字符串转换成一个2进制表示的日期类型字符串。这题有很强的条件限定，比如：总长度一定是10，下标4和7的位置的字符一定是“-”。我们可以充分利用这些条件来简化代码。

#include <string>
using namespace std;

class Solution {
public:
    string convertDateToBinary(string date) {
       return toBinary(stoi(date.substr(0, 4))) + "-" + toBinary(stoi(date.substr(5, 2))) + "-" + toBinary(stoi(date.substr(8, 2)));
    }

private:
    string toBinary(int num) {
        string result = "";
        while (num > 0) {
            if (num & 1) {
                result = "1" + result;
            } else {
                result = "0" + result;
            }
            num >>= 1;
        }
        return result;
    }
};

代码地址

https://github.com/f304646673/leetcode/tree/main/3280-Convert-Date-to-Binary/cplusplus