104 lines
3.3 KiB
Rust
104 lines
3.3 KiB
Rust
// https://www.reddit.com/r/dailyprogrammer/comments/7s888w/20180122_challenge_348_easy_the_rabbit_problem/
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use std::{thread, time, io};
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fn init(male: i128, female: i128, needed_alive: i128) -> ([i128; 96], [i128; 96], i128){
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let mut m: [i128; 96] = [0; 96];
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let mut f: [i128; 96] = [0; 96];
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m[2] = male;
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f[2] = female;
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return (m, f, needed_alive);
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}
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// reproduce, by letting all females 4 months and over have 9 female and 5 male descendants
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// fn reproduce(m_pop: [i128; 96], f_pop: [i128; 96]) -> ([i128; 96], [i128;96], i128, i128) {
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fn reproduce(m_pop: [i128; 96], f_pop: [i128; 96]) -> (i128, i128) {
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let mut res_m = 0;
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let mut res_f = 0;
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let f_iter = f_pop.iter().enumerate();
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for (i, count) in f_iter {
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if i < 95 && i > 3{
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// res_f[0] = res_f[0] + count * 9;
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// res_m[0] = res_m[0] + count * 5;
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res_m = res_m + count * 5;
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res_f = res_f + count * 9;
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}
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}
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return (res_m, res_f);
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}
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// age the bunny population by shifting the array one to the right
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fn age(m_pop: [i128; 96], f_pop: [i128; 96], new_males: i128, new_females: i128) -> ([i128; 96], [i128; 96]){
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let mut res_m: [i128; 96] = [0; 96];
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let mut res_f: [i128; 96] = [0; 96];
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res_m[0] = new_males;
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res_f[0] = new_females;
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let f_iter = f_pop.iter().enumerate();
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let m_iter = m_pop.iter().enumerate();
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for (i, count) in f_iter {
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if i < 95{
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res_f[i+1] = *count;
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}
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}
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for (i, count) in m_iter {
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if i < 95{
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res_m[i+1] = *count;
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}
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}
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return (res_m, res_f);
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}
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fn main() {
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// this whole part is just for reading from stdin...
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let mut input_m = String::new();
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let mut input_f = String::new();
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let mut input_n = String::new();
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println!("Enter the number of male rabbits to start with:");
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io::stdin().read_line(&mut input_m).expect("failed to read input");
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println!("Enter the number of female rabbits to start with:");
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io::stdin().read_line(&mut input_f).expect("failed to read input");
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println!("Enter the number of rabbits you want to reach:");
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io::stdin().read_line(&mut input_n).expect("failed to read input");
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let trim_m = input_m.trim();
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let trim_f = input_f.trim();
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let trim_n = input_n.trim();
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let trims = vec!(trim_m, trim_f, trim_n);
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let mut mf: Vec<i128> = vec!(10, 10, 10000);
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for (i, trim) in trims.iter().enumerate() {
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let g = &trim.parse::<i128>().unwrap_or(20);
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mf[i] = *g;
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}
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// . up until here
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let (mut m, mut f, n_a) = init(mf[0], mf[1], mf[2]);
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let mut sum_male: i128 = m.iter().sum();
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let mut sum_female: i128 = f.iter().sum();
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let mut sum = sum_male + sum_female;
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// println!("There are now {} rabbits alive!", sum);
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let mut i = 0;
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while sum < n_a {
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// this handling of tuples sucks, there's gotta be a better way...
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let (r_m, r_f) = reproduce(m, f);
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let (r_m, r_f) = age(m, f, r_m, r_f);
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m = r_m;
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f = r_f;
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sum_male = m.iter().sum();
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sum_female = f.iter().sum();
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sum = sum_male + sum_female;
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println!("There are now {} rabbits alive! {} males and {} females", sum, sum_male, sum_female);
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thread::sleep(time::Duration::from_millis(500));
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i += 1;
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}
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println!("It took {} months!", i);
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}
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