Initial commit with existing files

2025-12-06 17:43:57 -05:00 · 2020-06-06 17:15:36 -04:00
commit 321e91c098
33 changed files with 3616 additions and 0 deletions
--- a/Problem19.lua
+++ b/Problem19.lua
@@ -0,0 +1,186 @@
+--ProjectEuler/lua/Problem19.lua
+--Matthew Ellison
+-- Created: 03-13-19
+--Modified: 03-28-19
+--How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)?
+--[[
+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.
+]]
+--All of my requires, unless otherwise listed, can be found at https://bitbucket.org/Mattrixwv/luaClasses
+--[[
+	Copyright (C) 2019  Matthew Ellison
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Lesser General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Lesser General Public License for more details.
+
+	You should have received a copy of the GNU Lesser General Public License
+	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+]]
+
+
+require "Stopwatch"
+
+
+DAYS = {
+	SUNDAY = 0,
+	MONDAY = 1,
+	TUESDAY = 2,
+	WEDNESDAY = 3,
+	THURSDAY = 4,
+	FRIDAY = 5,
+	SATURDAY = 6,
+	NUMBER_OF_DAYS = 7,
+	ERROR = 8;
+}
+
+START_YEAR = 1901;
+END_YEAR = 2000;
+
+--Return the day of the week that the date you pass into it is on
+function getDay(month, day, year)
+	--Make sure the numbers are within propper bounds
+	if((month < 1) or (month > 12) or (day < 1) or (day > 31) or (year < 1)) then
+		return DAYS.ERROR;
+	end
+
+	numDays = 0;
+	currentYear = 1;
+	currentMonth = 1;
+	currentDay = DAYS.SATURDAY;
+	day = day - 1;
+
+	--Add the correct number of days for every year
+	while(currentYear < year) do
+		if(isLeapYear(currentYear)) then
+			numDays = numDays + 366;
+		else
+			numDays = numDays + 365;
+		end
+		currentYear = currentYear + 1;
+	end
+	--Add the correct number of days for every month
+	while(currentMonth < month) do
+		--February
+		if(currentMonth == 2) then
+			if(isLeapYear(currentYear)) then
+				numDays = numDays + 29;
+			else
+				numDays = numDays + 28;
+			end
+		--31 day months
+		elseif((currentMonth == 1) or (currentMonth == 3) or (currentMonth == 5) or (currentMonth == 7) or (currentMonth == 8) or (currentMonth == 10) or (currentMonth == 12)) then
+			numDays = numDays + 31;
+		--30 day months
+		else
+			numDays = numDays + 30;
+		end
+		currentMonth = currentMonth + 1;
+	end
+	--Account for the weird year of 1752
+	if(year > 1752) then
+		numDays = numDays - 11;
+	elseif(year == 1752) then
+		if(month > 9) then
+			numDays = numDays - 11;
+		elseif(month == 9) then
+			if(day >= 14) then
+				numDays = numDays - 11;
+			--Days 3-13 were skipped that year
+			elseif((day > 2) and (day < 14)) then
+				return DAYS.ERROR;
+			end
+		end
+	end
+	--Add the correct number of days for every day
+	numDays = numDays + day;
+
+	currentDay = currentDay + numDays;
+	currentDay = currentDay % DAYS.NUMBER_OF_DAYS;
+	if(currentDay == DAYS.SUNDAY) then
+		day =  DAYS.SUNDAY;
+	elseif(currentDay == DAYS.MONDAY) then
+		day = DAYS.MONDAY;
+	elseif(currentDay == DAYS.TUESDAY) then
+		day = DAYS.TUESDAY;
+	elseif(currentDay == DAYS.WEDNESDAY) then
+		day = DAYS.WEDNESDAY;
+	elseif(currentDay == DAYS.THURSDAY) then
+		day = DAYS.THURSDAY;
+	elseif(currentDay == DAYS.FRIDAY) then
+		day = DAYS.FRIDAY;
+	elseif(currentDay == DAYS.SATURDAY) then
+		day = DAYS.SATURDAY;
+	else
+		day = DAYS.ERROR;
+	end
+	--Return the day generated
+	return day;
+end
+
+function isLeapYear(year)
+	if(year < 1) then
+		answer = false;
+	elseif((year % 100) == 0) then
+		--This rule only applies at and after 1800
+		if(year <= 1700) then
+			answer = true;
+		elseif((year % 400) == 0) then
+			answer = true;
+		else
+			answer = false;
+		end
+	elseif((year % 4) == 0) then
+		answer = true;
+	else
+		answer = false;
+	end
+	return answer;
+end
+
+--Setup the variables
+timer = Stopwatch:create();
+totalSundays = 0;
+
+--Start the timer
+timer:start();
+
+--Run for all years up to 2000
+for year=START_YEAR,END_YEAR do
+	--Run for all months in the year
+	for month=1,12 do
+		day = getDay(month, 1, year);
+		if(day == DAYS.ERROR) then
+			io.output("There was an error with the day\n");
+			os.exit();
+		elseif(day == DAYS.SUNDAY) then
+			totalSundays = totalSundays + 1;
+		end
+	end
+end
+
+--Stop the timer
+timer:stop()
+
+--Print the results
+io.write("There are " .. totalSundays .. " Sundays that landed on the first of the months from " .. START_YEAR .. " to " .. END_YEAR .. '\n');
+io.write("It took " .. timer:getMilliseconds() .. " milliseconds to run this algorithm\n");
+
+--[[ Results:
+There are 171 Sundays that landed on the first of the months from 1901 to 2000
+It took 390.0 milliseconds to run this algorithm
+]]