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Formatted question description: https://leetcode.ca/all/1507.html

1507. Reformat Date (Easy)

Given a date string in the form Day Month Year, where:

  • Day is in the set {"1st", "2nd", "3rd", "4th", ..., "30th", "31st"}.
  • Month is in the set {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}.
  • Year is in the range [1900, 2100].

Convert the date string to the format YYYY-MM-DD, where:

  • YYYY denotes the 4 digit year.
  • MM denotes the 2 digit month.
  • DD denotes the 2 digit day.

 

Example 1:

Input: date = "20th Oct 2052"
Output: "2052-10-20"

Example 2:

Input: date = "6th Jun 1933"
Output: "1933-06-06"

Example 3:

Input: date = "26th May 1960"
Output: "1960-05-26"

 

Constraints:

  • The given dates are guaranteed to be valid, so no error handling is necessary.

Related Topics:
String

Solution 1.

  • class Solution {
        public String reformatDate(String date) {
            String[] months = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
            Map<String, Integer> map = new HashMap<String, Integer>();
            for (int i = 1; i <= 12; i++)
                map.put(months[i - 1], i);
            String[] array = date.split(" ");
            int year = Integer.parseInt(array[2]);
            int month = map.get(array[1]);
            int day = Integer.parseInt(array[0].substring(0, array[0].length() - 2));
            return String.format("%d-%02d-%02d", year, month, day);
        }
    }
    
    ############
    
    class Solution {
        public String reformatDate(String date) {
            var s = date.split(" ");
            String months = " JanFebMarAprMayJunJulAugSepOctNovDec";
            int day = Integer.parseInt(s[0].substring(0, s[0].length() - 2));
            int month = months.indexOf(s[1]) / 3 + 1;
            return String.format("%s-%02d-%02d", s[2], month, day);
        }
    }
    
  • // OJ: https://leetcode.com/problems/reformat-date/
    // Time: O(1)
    // Space: O(1)
    class Solution {
    public:
        string reformatDate(string date) {
            istringstream ss(date);
            string day, mon, year, m;
            ss >> day >> mon >> year;
            if (mon == "Jan") m = "01";
            else if (mon == "Feb") m = "02";
            else if (mon == "Mar") m = "03";
            else if (mon == "Apr") m = "04";
            else if (mon == "May") m = "05";
            else if (mon == "Jun") m = "06";
            else if (mon == "Jul") m = "07";
            else if (mon == "Aug") m = "08";
            else if (mon == "Sep") m = "09";
            else if (mon == "Oct") m = "10";
            else if (mon == "Nov") m = "11";
            else m = "12";
            string d = to_string(stoi(day));
            return year + "-" + m + "-" + (d.size() == 1? "0" + d : d);
        }
    };
    
  • class Solution:
        def reformatDate(self, date: str) -> str:
            s = date.split()
            s.reverse()
            months = " JanFebMarAprMayJunJulAugSepOctNovDec"
            s[1] = str(months.index(s[1]) // 3 + 1).zfill(2)
            s[2] = s[2][:-2].zfill(2)
            return "-".join(s)
    
    
    
  • func reformatDate(date string) string {
    	s := strings.Split(date, " ")
    	day, _ := strconv.Atoi(s[0][:len(s[0])-2])
    	months := " JanFebMarAprMayJunJulAugSepOctNovDec"
    	month := strings.Index(months, s[1])/3 + 1
    	year, _ := strconv.Atoi(s[2])
    	return fmt.Sprintf("%d-%02d-%02d", year, month, day)
    }
    
  • class Solution {
        /**
         * @param String $date
         * @return String
         */
        function reformatDate($date) {
            $arr = explode(" ", $date);
            $months = array("Jan" => "01", "Feb" => "02", "Mar" => "03", "Apr" => "04", "May" => "05", "Jun" => "06", "Jul" => "07", "Aug" => "08", "Sep" => "09", "Oct" => "10", "Nov" => "11", "Dec" => "12");
            $year = $arr[2];
            $month = $months[$arr[1]];
            $day = intval($arr[0]);
            if ($day > 0 && $day < 10) $day = "0".$day;
            return $year."-".$month."-".$day;
        }
    }
    
  • function reformatDate(date: string): string {
        const s = date.split(' ');
        const months = ' JanFebMarAprMayJunJulAugSepOctNovDec';
        const day = parseInt(s[0].substring(0, s[0].length - 2));
        const month = Math.floor(months.indexOf(s[1]) / 3) + 1;
        return `${s[2]}-${month.toString().padStart(2, '0')}-${day
            .toString()
            .padStart(2, '0')}`;
    }
    
    

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