part 2 in rust

2025/7/gleam/src/main.gleam

···
 import gleam/int
 import gleam/io
 import gleam/list
-import gleam/result
 import gleam/set
 import gleam/string
 import simplifile as file
···
 
   let timelines =
     splitters_map
-    |> list.fold(dict.new() |> dict.insert(0, start), fn(timelines, splitters) {
-      // echo #(timelines, splitters)
-      timelines
-      |> dict.fold(timelines, fn(timelines, timeline, beam) {
-        case splitters |> set.contains(beam) {
-          False -> timelines
-          True -> {
-            timelines
-            |> dict.delete(timeline)
-            |> dict.insert(
-              int.random(100_000_000_000_000_000_000_000),
-              beam - 1,
-            )
-            |> dict.insert(
-              int.random(100_000_000_000_000_000_000_000),
-              beam + 1,
-            )
+    |> list.index_fold(
+      dict.new() |> dict.insert("", start),
+      fn(timelines, splitters, i) {
+        echo i
+        // echo #(timelines, splitters)
+        timelines
+        |> dict.fold(timelines, fn(timelines, timeline, beam) {
+          case splitters |> set.contains(beam) {
+            False -> timelines
+            True -> {
+              timelines
+              |> dict.delete(timeline)
+              |> dict.insert(timeline <> "-", beam - 1)
+              |> dict.insert(timeline <> "+", beam + 1)
+            }
           }
-        }
-      })
-    })
+        })
+      },
+    )
   echo timelines
   timelines
   |> dict.size

2025/7/rust/Cargo.lock

···
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "rust"
+version = "0.1.0"

2025/7/rust/Cargo.toml

···
+[package]
+name = "rust"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

2025/7/rust/src/main.rs

···
+use std::{
+    char,
+    collections::{HashMap, HashSet},
+};
+
+fn main() {
+    let input = include_str!("../../input_example.txt").trim();
+
+    let mut input: Vec<&str> = input.trim().split("\n").collect();
+    let start = input[0].find("S").unwrap() as u32;
+    let splitters_map: Vec<HashSet<u32>> = input[0..input.len()]
+        .iter()
+        .enumerate()
+        .map(|(i, line)| if i % 2 != 0 { "" } else { line })
+        .filter(|line| line != &"")
+        .map(|line| {
+            line.chars()
+                .enumerate()
+                .fold(HashSet::new(), |mut s, (i, char)| {
+                    if char == '^' {
+                        s.insert(i as u32);
+                    }
+                    s
+                })
+        })
+        .collect();
+
+    let timelines = {
+        let mut timelines: HashMap<String, u32> = HashMap::new();
+        timelines.insert("".to_string(), start);
+        for splitters in splitters_map {
+            for (timeline, pos) in timelines.clone() {
+                if splitters.contains(&pos) {
+                    timelines.remove(&timeline);
+                    timelines.insert(format!("{timeline}+"), pos + 1);
+                    timelines.insert(format!("{timeline}-"), pos - 1);
+                }
+            }
+        }
+        timelines
+    };
+    println!("{}", timelines.len());
+}