day22 part1

src/main.rs

@@ -1,4 +1,4 @@
 fn main() {
-    aoc_2018::tasks::day20::task1();
+    aoc_2018::tasks::day22::task1();
     // aoc_2018::tasks::day15::task2();
 }

src/tasks/day22.rs

@@ -0,0 +1,32 @@
+pub fn task1() {
+    let depth: usize = 3879;
+    //let target: (usize, usize) = (8, 713);
+    const TARGET_X: usize = 8;
+    const TARGET_Y: usize = 713;
+
+    let mut map: Vec<Vec<usize>> = Vec::with_capacity(TARGET_X + 1);
+    let mut inner_vec = Vec::with_capacity(TARGET_Y + 1);
+    inner_vec.resize(TARGET_Y + 1, 0);
+    map.resize(TARGET_X + 1, inner_vec);
+
+    for x in 0..=TARGET_X {
+        for y in 0..=TARGET_Y {
+            let geo_index = match (x, y) {
+                (0, 0) => 0,
+                (TARGET_X, TARGET_Y) => 0,
+                (x, 0) => x * 16807,
+                (0, y) => y * 48271,
+                (x, y) => map[x - 1][y] * map[x][y - 1],
+            };
+            let erosion_index = (geo_index + depth) % 20183;
+            map[x][y] = erosion_index;
+        }
+    }
+
+    // println!("{:?}", map);
+
+    let result: usize = (0..=TARGET_X)
+        .map(|x| (0..=TARGET_Y).map(|y| map[x][y] % 3).sum::<usize>())
+        .sum();
+    println!("Sum of erosion indexes: {}", result);
+}

src/tasks/mod.rs

@@ -14,3 +14,4 @@ pub mod day13;
 pub mod day14;
 pub mod day15;
 pub mod day20;
+pub  mod day22;