problem19 (Counting Sundays)

problem19 (Counting Sundays)

You are given the following information, but you may prefer to do some research for yourself.
1 Jan 1900 was a Monday.
Thirty days has September,
April, June and November.
All the rest have thirty-one,
Saving February alone,
Which has twenty-eight, rain or shine.
And on leap years, twenty-nine.
A leap year occurs on any year evenly divisible by 4, but not on a century unless it is divisible by 400.
How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)





In Python
# Counting Sunday
import time

startTime = time.time()
days = 1
count = 0
for year in range(1900, 2001):
    for month in range(1, 13):
        if month == 1 or month == 3 or month == 5 or month == 7 or month == 8 or month == 10 or month == 12:
            days += 31
        elif month == 4 or month == 6 or month == 9 or month == 11:
            days += 30
        elif month == 2 and year % 4 == 0 and year != 1900:
            days += 29
        else:
            days += 28
        if days % 7 == 0 and year > 1900:
            count += 1
print(count)
print(time.time() - startTime, "seconds")

Run time: 0.0008108615875244141 seconds



In Java:

//Euler19 Counting Sunday
package project_euler11_20;

public class Euler19 {
	public static void main(String[] args) {
		int days = 1;
		int count = 0;
		long startTime = System.currentTimeMillis();
		for (int i = 1900; i < 2001; i++) {
			for (int j = 1; j < 13; j++) {
				switch(j) {
					case 1: case 3: case 5: case 7: case 8: case 10: case 12:
						days += 31; break;
					case 4: case 6: case 9: case 11:
						days += 30; break;
					case 2:
						if(i % 4 == 0 && i != 1900) {
						days += 29;
						} else {
							days += 28;
						} break;
				}
				if (days % 7 == 0 && i > 1900) {
					count++;
				}
			}
		}
		System.out.println(count);
		long endTime = System.currentTimeMillis();
		System.out.println((double)(endTime - startTime)/(double)1000 + "seconds");
	}

}
Run time : 0.0seconds

solution: 171