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102 lines
3.0 KiB
Rust
102 lines
3.0 KiB
Rust
//ProjectEulerRust/src/Problems/Problems21.rs
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//Matthew Ellison
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// Created: 06-17-20
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//Modified: 06-17-20
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//Evaluate the sum of all the amicable numbers under 10000
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//Unless otherwise listed all non-standard includes are my own creation and available from https://bibucket.org/Mattrixwv/RustClasses
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/*
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Copyright (C) 2020 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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extern crate myClasses;
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use crate::Problems::Answer::Answer;
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pub fn getDescription() -> String{
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"Evaluate the sum of all the amicable numbers under 10000".to_string()
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}
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pub fn solve() -> Answer{
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let LIMIT = 10000;
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//Setup the variables
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let mut divisorSum = Vec::<i64>::new();
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//Make sure the array is filled with 0's
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while(divisorSum.len() < LIMIT){
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divisorSum.push(0);
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}
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//Start the timer
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let mut timer = myClasses::Stopwatch::Stopwatch::new();
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timer.start();
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//Generate the divisors of all numbers < 10000, get their sum, and add it to the list
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for cnt in 1..LIMIT{
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let mut divisors = myClasses::Algorithms::getDivisors(cnt as i64);
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if(divisors.len() > 1){
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divisors.remove(divisors.len() - 1);
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}
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divisorSum[cnt] = divisors.iter().sum();
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}
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//Check every sum of divisors in the list for matching sum
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let mut amicable = Vec::<i64>::new();
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for cnt in 1..divisorSum.len(){
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let sum = divisorSum[cnt];
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//If the sum is greater than the number of divisors then it is impossible to be amicable. Skip the number and continue
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if(sum >= divisorSum.len() as i64){
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continue;
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}
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//We know that divisorSum.at(cnt) == sum, so if divisorSum.at(sum) == cnt we found an amicable number
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if(divisorSum[sum as usize] == cnt as i64){
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//A number can't be amicable with itself
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if(sum == cnt as i64){
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continue;
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}
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//Add it to the array of amicable numbers
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amicable.push(cnt as i64);
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}
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}
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//Stop the timer
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timer.stop();
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//Sort the array for neatness
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amicable.sort();
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//Return the results
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let mut answerString = format!("All amicable numbers less than {} are\n", LIMIT);
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for cnt in 0..amicable.len(){
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answerString = format!("{}{}\n", answerString, amicable[cnt]);
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}
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answerString = format!("{}The sum of all of these amicable numbers is {}", answerString, amicable.iter().sum::<i64>());
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return Answer::new(answerString, timer.getString());
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}
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/* Results:
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All amicable numbers less than 10000 are
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220
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284
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1184
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1210
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2620
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2924
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5020
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5564
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6232
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6368
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The sum of all of these amicable numbers is 31626
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It took 5.792 milliseconds to solve this problem
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*/
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