打印日期

常规思路，判闰年，逐月减，小零止，规整出
public class Main {

    public static int isYear(int year) {
        if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
            return 1;
        }else {
            return 0;
        }
    }

    public static void main(String[] args) {
        int monthDay[][] = {{31,28,31,30,31,30,31,31,30,31,30,31},
                {31,29,31,30,31,30,31,31,30,31,30,31}};
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()) {
            int year,dayNumber;
            year = scanner.nextInt();
            dayNumber = scanner.nextInt();

            for (int month = 0;month<12;month++){
                if ((dayNumber - monthDay[isYear(year)][month])>0) {
                    dayNumber -= monthDay[isYear(year)][month];
                }else {
//                    System.out.println(year+"-"+(month+1)+"-"+dayNumber);
                    System.out.printf("%04d-%02d-%02d\n",year,month+1,dayNumber);
                    break;
                }
            }
        }
        scanner.close();
    }
} 

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

public static void main(String[] args) throws IOException {
    BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
    String line = null;
    int day[]={31,29,31,30,31,30,31,31,30,31,30,31};
    while ((line = input.readLine()) != null) {
        int year= Integer.parseInt(line.split(" ")[0]);
        int date= Integer.parseInt(line.split(" ")[1]);
        if((year%100!=0&&year%4==0)||year%400==0){
            day[1]=29;
        }else{
            day[1]=28;
        }
        String d=year+"-";
        for(int i=0;i<12;i++){
            if(date<=day[i]){
                if(i<9){
                    d+="0"+(i+1)+"-";
                }else{
                    d+=(i+1)+"-";
                }
                if(date<10){
                    d+="0"+date;
                }else{
                    d+=date;
                }
                System.out.println(d);
                break;
            }else{
                date-=day[i];
            }
        }
    }
    input.close();
}

}

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

public class Main {
	
	public static void main(String[] args) throws Exception{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String line = null;
  
        while ((line = br.readLine()) != null) {
              
            String[] arrStr = line.split(" ");
              
            int year = Integer.parseInt(arrStr[0]);
            int n = Integer.parseInt(arrStr[1]);
            String s = test(year, n); 
            System.out.println(s);
              
        }
	
	}
	public static String test(int year, int n) {
		
		String str = "-1";
		int month = 1;
		int maxMonthDay = 0;
		int amountDay = 0;
		
		DateFormat dateformat = new SimpleDateFormat("yyyy-MM-dd");
		Calendar calendar = new GregorianCalendar();
		
		try {
			/*
			 * 获取月份
			 */
			while(true){
				//year-month-1
				str = year + "-" + month + "-1";
				//字符串转为日期
				Date date = dateformat.parse(str);
				calendar.setTime(date);
				
				//获取每一个月的天数
				maxMonthDay = calendar.getActualMaximum(Calendar.DATE);
				if(n<(amountDay+maxMonthDay)){
					break;
				}
				amountDay += maxMonthDay;
				month++;
			}
			
			int day2 = n - amountDay;
			str = year + "-" + month + "-" + day2;
			Date d = dateformat.parse(str);
            String s = dateformat.format(d);
			return s;
			
		} catch (ParseException e) {
			e.printStackTrace();
		}
		return null;
	}
}

import java.util.Scanner;

public class Main {

	@SuppressWarnings("resource")
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int year = scanner.nextInt();
		int day = scanner.nextInt();
		int nowMonth = 0;
		int nowDay = 0;
		/*
		 * 建立一个数组，表示出所有的月份的天数
		 */
		int[] allMonthDays = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
		if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
			if (day > 59) {
				allMonthDays[1] = 29;
			}
		}
		int sum = 0;
		int i;
		for (i = 0; i < allMonthDays.length; i++) {
			if (sum < day) {
				sum += allMonthDays[i];
			} else {
				nowMonth = i;
				nowDay = allMonthDays[i - 1] - sum + day;
				break;
			}
		}
		if (i == 12) {
			nowMonth = 12;
			nowDay = allMonthDays[i - 1] - sum + day;
		}

		if (nowDay < 10 && nowMonth >= 10) {
			System.out.println(year + "-" + nowMonth + "-0" + nowDay);
		} else if (nowDay < 10 && nowMonth < 10) {
			System.out.println(year + "-0" + nowMonth + "-0" + nowDay);
		} else if (nowDay >= 10 && nowMonth < 10) {
			System.out.println(year + "-0" + nowMonth + "-" + nowDay);
		} else {
			System.out.println(year + "-" + nowMonth + "-" + nowDay);
		}
	}
}

}

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		Calendar cld = Calendar.getInstance();
		while (in.hasNext()) {
			cld.set(in.nextInt(), 0, in.nextInt());
			System.out.println(sdf.format(cld.getTime()));
		}
	}
} 

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Scanner;


public class Main {
	
	private static String defaultDatePattern = "yyyy-MM-dd"; 
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		Main m = new Main();
		while(sc.hasNext()){
			int year = sc.nextInt();
			int day = sc.nextInt();
			m.outCalendar(year, day);
		}
		sc.close();
	}

	public void outCalendar(int year, int day) {
		Calendar c = Calendar.getInstance();
		c.set(year, 0, day);
		Date d = c.getTime();
		SimpleDateFormat df=new SimpleDateFormat(defaultDatePattern);
		System.out.println(df.format(d));
	}
	
} 

/**
只要建立一个数组，用于查表就好,把闰年的情况独立出来，也就是说把二月改一下即可。
而且天数只会最多有366天，也就是加一年而已，完全不用再考虑第二年情况！！
*/
import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		while(in.hasNext()){
			fun(in.nextInt(), in.nextInt());
		}
		in.close();
	}
	
	public static void fun(int a, int b){
		int[] month = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
		if(a % 4 == 0 && a % 100 != 0 || a % 400 == 0)
			month[1] = 29;
		int i;
		for(i = 0; i < 12; i++){
			if(b <= month[i])
				break;
			else
				b -= month[i];
		}
		if(i == 11 && b > 31)
			a++;
		String str = String.format("%d-%02d-%02d",a, i+1, b);
		System.out.println(str);
	}
}

import java.util.Scanner;

public class Main
{
    static int[] M = {31,28,31,30,31,30,31,31,30,31,30,31};
    static int[] N = {31,29,31,30,31,30,31,31,30,31,30,31};
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        while(scan.hasNext()){
            String[] line = scan.nextLine().split(" ");
            if(line.length == 2){
                int year = Integer.parseInt(line[0]);
                int index = Integer.parseInt(line[1]);
                getDate(year,index);
            }
        }
    }
    
    private static void getDate(int _year, int _index){
        if(_year < 1 || _year > 3000)
            return;
        if(_index < 1 || _index > 366)
            return;

		System.out.print(_year+"-");
        if(!isRunNian(_year)){
            getMD(_index,M);
        }else{
            getMD(_index,N);
        }
    }

	private static void getMD(int _index,int[] A){
		int day = _index;
        for(int i=0;i<A.length;i++){
            if(day > A[i]){
                day -= A[i];
            }else{
                System.out.println(trans((i+1))+"-"+trans(day));
                break;
            }
        }
	
	}

	private static String trans(int _x){
		return _x < 10?"0"+_x:String.valueOf(_x);
	}
    
    
    private static boolean isRunNian(int _year){
        if(_year % 400 == 0)
        	return true;
        
        if(_year % 4 == 0){
        	if(_year % 100 == 0)
                return false;
            return true;
        }
        return false;
    }
    
    
    
}