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120 lines
3.6 KiB
C++
120 lines
3.6 KiB
C++
//ProjectEuler/C++/Source/Problem25.cpp
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//Matthew Ellison
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// Created: 11-13-18
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//Modified: 07-14-19
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//What is the index of the first term in the Fibonacci sequence to contain 1000 digits?
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//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/myClasses
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//This file contains a header from the gmp library. The library is used for large integers.
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//You can find more information about them at https://gmplib.org/
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//When compiling this file you need to have the gmp library installed as well as linking the libraries to your executable using the -lgmpxx and -lgmp flags
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/*
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Copyright (C) 2019 Matthew Ellison
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <string>
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#include <sstream>
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#include "gmpxx.h"
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#include "Algorithms.hpp"
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#include "Stopwatch.hpp"
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#include "../Headers/Problem25.hpp"
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unsigned int Problem25::NUM_DIGITS = 1000; //The number of digits to calculate up to
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Problem25::Problem25() : Problem("What is the index of the first term in the Fibonacci sequence to contain 1000 digits?"), number(0), index(2){
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}
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void Problem25::solve(){
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//If the problem has already been solved do nothing and end the function
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if(solved){
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return;
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}
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//Start the timer
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timer.start();
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//Move through all Fibonacci numbers until you reach the one with at least NUM_DIGITS digits
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while(number.get_str().size() < NUM_DIGITS){
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++index; //Increase the index number. Doing this at the beginning keeps the index correct at the end of the loop
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number = mee::getFib(index); //Calculate the number
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}
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//Stop the timer
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timer.stop();
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//Throw a flag to show the problem is solved
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solved = true;
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}
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std::string Problem25::getString() const{
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//If the problem hasn't been solved throw an exception
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if(!solved){
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throw unsolved();
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}
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std::stringstream results;
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results << "The first Fibonacci number with " << NUM_DIGITS << " digits is " << number
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<< "\nIts index is " << index;
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return results.str();
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}
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//Returns the Fibonacci number asked for
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mpz_class Problem25::getNumber() const{
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//If the problem hasn't been solved throw an exception
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if(!solved){
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throw unsolved();
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}
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return number;
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}
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//Returns the Fibonacci number asked for as a string
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std::string Problem25::getNumberString() const{
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//If the problem hasn't been solved throw an exception
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if(!solved){
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throw unsolved();
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}
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return number.get_str();
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}
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//Returns the index of the requested Fibonacci number
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mpz_class Problem25::getIndex() const{
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//If the problem hasn't been solved throw an exception
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if(!solved){
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throw unsolved();
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}
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return index;
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}
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//Returns the index of the requested Fibonacci number as a string
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std::string Problem25::getIndexString() const{
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//If the problem hasn't been solved throw an exception
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if(!solved){
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throw unsolved();
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}
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return index.get_str();
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}
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//Returns the index of the requested Fibonacci number as a uint64_t
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uint64_t Problem25::getIndexInt() const{
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//If the problem hasn't been solved throw an exception
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if(!solved){
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throw unsolved();
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}
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return index.get_ui();
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}
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