gistfile1.txt

Use std::collections::HashMap;

struct RangeTuple<T> {
    cache: HashMap<(T, T), bool>,
    first: std::ops::Range<T>,
    second: std::ops::Range<T>,
}

impl<T: Hash + Eq> RangeTuple<T> {
    fn new(f: std::ops::Range<T>, s: std::ops::Range<T>) -> RangeTuple<T> {
        RangeTuple { first: f, second: s, cache: HashMap<(T, T), bool> = HashMap::new() }
    }
}

impl<T> Iterator for RangeTuple<T> {
    type Item = (T, T);

    fn next(&mut self) -> Option<(T, T)> {
        Some((self.first.next(), self.second.next()))
    }
}

fn is_palindrome(num: u64) -> bool {
    let s = num.to_string();
    s.chars().zip(s.chars().rev()).all(|(i1, i2)| i1 == i2 )
}

fn main() {
    let mut largest = 0;
    for i in 100..999 {
        for j in 100..999 {
            if is_palindrome(i * j) && ((i * j) > largest) {
                largest = i * j;
                println!("Largest: {}, {} x {}", largest, i, j);
            }
        }
    }
}