Project Euler & HackerRank problem 19 solution: Counting Sundays solved using Python

Project-Euler-Problem-19.py

import datetime as dt

delta, c, targetDOW, targetDate = dt.timedelta(days=1), 0, 6, 1
yS, mS, dS,   yE, mE, dE = 1901,1,1,   2000,12,31
yearDelta = yE-yS  # number of years
yS = (yS%400) + 400  # normalized and non-zero

a = dt.datetime(yS, mS, dS)
b = dt.datetime(yS+yearDelta, mE, dE)
while a <= b:
	if a.day==targetDate and a.weekday()==targetDOW:
		c+= 1
		delta = dt.timedelta(days=7)
	a+= delta

print (["Mon","Tue","Wed","Thu","Fri","Sat","Sun"][targetDOW],"on day", targetDate, "of the month:", c)