Are there as many days in the first half of leap year as in the second half?

It's different. According to the Gregorian calendar, there are 366 days in a leap year, including 182 days in the first half and 184 days in the second half, so the days in the first half and the second half are different. The establishment of leap year is to make up for the time difference between the number of days in a year and the actual period of revolution of the earth caused by man-made calendar regulations.