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ProjectEulerJava/Problem5.java

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2.3 KiB
Java

//ProjectEuler/Java/Problem5.java
//Matthew Ellison
// Created: 03-01-19
//Modified: 03-28-19
//What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?
//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/JavaClasses
/*
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/>.
*/
import mattrixwv.Stopwatch;
import java.util.ArrayList;
public class Problem5{
public static void main(String[] argv){
Stopwatch timer = new Stopwatch(); //So you can time the code
//Start the timer
timer.start();
//Start at 20 because it must at least be divisible by 20. Increment by 2 because it must be an even number to be divisible by 2
Boolean numFound = false;
Integer currentNum = 20;
while((currentNum > 0) && (!numFound)){
//Start by assuming you found the number (because we throw a flag if we didn't find it)
numFound = true;
//Step through every number from 1-20 seeing if the current number is divisible by it
for(Integer divisor = 1;divisor <= 20;++divisor){
//If it is not divisible then throw a flag and start looking at the next number
if((currentNum % divisor) != 0){
numFound = false;
break;
}
}
//If you didn't find the correct numbe then increment by 2
if(!numFound){
currentNum += 2;
}
}
//Stop the timer
timer.stop();
//Print the results
System.out.println("The smallest positive number evenly divisibly by all number 1-20 is " + currentNum.toString());
System.out.println("It took " + timer.getStr() + " to run this algorithm");
}
}
/* Results:
The smallest positive number evenly divisibly by all number 1-20 is 232792560
It took 1.987 seconds to run this algorithm
*/