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-rw-r--r--2023/day9/src/lib.rs122
1 files changed, 122 insertions, 0 deletions
diff --git a/2023/day9/src/lib.rs b/2023/day9/src/lib.rs
new file mode 100644
index 0000000..a1b0588
--- /dev/null
+++ b/2023/day9/src/lib.rs
@@ -0,0 +1,122 @@
+pub fn part1(input: &str) -> i32 {
+ let mut res: i32 = 0;
+
+ let m: Vec<Vec<i32>> = input
+ .trim_end()
+ .split('\n')
+ .map(|x| {
+ x.split(' ')
+ .map(|y| y.parse::<i32>().unwrap())
+ .collect::<Vec<i32>>()
+ })
+ .collect();
+
+ for i in m {
+ let mut aux: Vec<Vec<i32>> = vec![i];
+
+ let mut z = 1;
+ loop {
+ aux.push(vec![]);
+ for j in 1..aux[z - 1].len() {
+ let x = aux[z - 1][j] - aux[z - 1][j - 1];
+ aux[z].push(x);
+ }
+
+ if aux[z].iter().filter(|&k| *k != 0).count() == 0 {
+ aux[z].push(0);
+ break;
+ }
+
+ z += 1;
+ }
+
+ let n = aux.len() - 1;
+ for j in (0..n).rev() {
+ let t = aux[j + 1][aux[j + 1].len() - 1];
+ let r = aux[j][aux[j].len() - 1];
+ aux[j].push(t + r);
+ }
+
+ res += aux[0][aux[0].len() - 1];
+ }
+
+ res
+}
+
+pub fn part2(input: &str) -> i32 {
+ let mut res: i32 = 0;
+
+ let m: Vec<Vec<i32>> = input
+ .trim_end()
+ .split('\n')
+ .map(|x| {
+ x.split(' ')
+ .map(|y| y.parse::<i32>().unwrap())
+ .collect::<Vec<i32>>()
+ })
+ .collect();
+
+ for i in m {
+ let mut aux: Vec<Vec<i32>> = vec![i];
+
+ let mut z = 1;
+ loop {
+ aux.push(vec![]);
+ for j in 1..aux[z - 1].len() {
+ let x = aux[z - 1][j] - aux[z - 1][j - 1];
+ aux[z].push(x);
+ }
+
+ if aux[z].iter().filter(|&k| *k != 0).count() == 0 {
+ aux[z].push(0);
+ break;
+ }
+
+ z += 1;
+ }
+
+ let n = aux.len() - 1;
+ for j in (0..n).rev() {
+ let t = aux[j + 1][0];
+ let r = aux[j][0];
+ aux[j].insert(0, r - t);
+ }
+
+ res += aux[0][0];
+ }
+
+ res
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn example_part1() {
+ let input = include_str!("../example.txt");
+ let result = part1(input);
+ assert_eq!(result, 114);
+ }
+
+ #[test]
+ fn input_part1() {
+ let input = include_str!("../input.txt");
+ let result = part1(input);
+ assert_eq!(result, 2008960228);
+ }
+
+ #[test]
+ fn example_part2() {
+ let input = include_str!("../example.txt");
+ let result = part2(input);
+ assert_eq!(result, 2);
+ }
+
+ #[test]
+ fn input_part2() {
+ let input = include_str!("../input.txt");
+ let result = part2(input);
+ assert_eq!(result, 71585);
+ }
+}