64 lines
1.3 KiB
Rust
64 lines
1.3 KiB
Rust
fn main() {
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part1(246515, 739105);
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part2(246515, 739105);
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}
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fn digit_n(digit: u32, n: usize) -> usize {
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let place = 10usize.pow(5 - digit);
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(n / place) % 10
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}
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fn is_increasing(n: usize) -> bool {
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for digit in 0 .. 5 {
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let this = digit_n(digit, n);
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let next = digit_n(digit + 1, n);
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if next < this {
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return false;
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}
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}
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true
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}
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fn has_double(n: usize) -> bool {
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for digit in 0 .. 5 {
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let this = digit_n(digit, n);
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let next = digit_n(digit + 1, n);
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if next == this {
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return true;
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}
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}
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false
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}
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fn has_strict_double(n: usize) -> bool {
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let mut doubles: [usize; 10] = Default::default();
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for digit in 0 .. 5 {
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let this = digit_n(digit, n);
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let next = digit_n(digit + 1, n);
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if next == this {
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doubles[this] += 1;
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}
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}
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doubles.contains(&1)
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}
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fn part1(lower: usize, upper: usize) {
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let mut count = 0;
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for n in lower ..= upper {
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if is_increasing(n) && has_double(n) {
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count += 1;
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}
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}
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println!("Part 1: {}", count);
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}
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fn part2(lower: usize, upper: usize) {
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let mut count = 0;
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for n in lower ..= upper {
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if is_increasing(n) && has_strict_double(n) {
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count += 1;
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}
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}
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println!("Part 2: {}", count);
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}
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