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96 lines
2.2 KiB
C++
96 lines
2.2 KiB
C++
//myClasses/Algorithms.hpp
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//Matthew Ellison
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// Created: 11-8-18
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//Modified: 11-8-18
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//This file contains the declarations to several algoritms that I have found useful
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#ifndef MEE_ALGORITHMS_HPP
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#define MEE_ALGORITHMS_HPP
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#include <vector>
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#include <cinttypes>
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namespace mee{
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template<class T>
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std::vector<T> getPrimes(T goalNumber){
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std::vector<T> primes;
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bool foundFactor = false;
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//If the number is 0 or a negative number return an empty vector
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if(goalNumber < 1){
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return primes;
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}
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//1 divides everything
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primes.push_back(1);
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//If the number is even 2 is a factor
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if((goalNumber % 2) == 0){
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primes.push_back(2);
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}
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//We can now start at 3 and skip all of the even numbers
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for(T possiblePrime = 3;possiblePrime <= goalNumber;possiblePrime += 2){
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//Step through every element in the current primes. If you don't find anything that divides it, it must be a prime itself
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for(uint64_t cnt = 0;(cnt < primes.size()) && ((primes.at(cnt) * primes.at(cnt)) < goalNumber);++cnt){
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if((possiblePrime % primes.at(cnt)) == 0){
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foundFactor = true;
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break;
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}
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}
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//If you didn't find a factor then it must be prime
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if(!foundFactor){
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primes.push_back(possiblePrime);
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}
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//If you did find a factor you need to reset the flag
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else{
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foundFactor = false;
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}
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}
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return primes;
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}
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template<class T>
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std::vector<T> getDivisors(T num){
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std::vector<T> divisors; //Holds the number of divisors
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//You only need to go to sqrt(number). cnt * cnt is faster than sqrt()
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for(int cnt = 1;cnt * cnt <= num;++cnt){
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//Check if the counter evenly divides the number
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//If it does the counter and the other number are both divisors
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if((num % cnt) == 0){
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if(!isFound(cnt, divisors)){
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divisors.push_back(cnt);
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}
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if(!isFound(num/cnt, divisors)){
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divisors.push_back(num / cnt);
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}
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}
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}
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return divisors;
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}
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template <class T>
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T getSum(std::vector<T> numbers){
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T sum = 0;
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for(unsigned int cnt = 0;cnt < numbers.size();++cnt){
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sum += numbers.at(cnt);
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}
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return sum;
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}
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template<class T>
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bool isFound(T num, std::vector<T> list){
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for(int cnt = 0;cnt < list.size();++cnt){
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if(list.at(cnt) == num){
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return true;
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}
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}
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return false;
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}
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}
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#endif //MEE_ALGORITHMS_HPP
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