2024-{23,24,25}-1

Author: fornwall

crates/core/src/year2024/day23.rs

@@ -1,18 +1,101 @@
-use crate::input::Input;
+use std::collections::{HashMap, HashSet};
 
-pub const fn solve(_input: &Input) -> Result<u32, String> {
-    Ok(0)
+use crate::{
+    common::{array_stack::ArrayStack, id_assigner::IdAssigner},
+    input::{on_error, Input},
+    year2017::disjoint_set::DisjointSet,
+};
+
+pub fn solve(input: &Input) -> Result<u32, String> {
+    let mut with_t = ArrayStack::<1000, u16>::new();
+    let mut to_adjacency = HashMap::new();
+
+    for line in input.text.lines() {
+        let (s1, s2) = line.split_once('-').ok_or_else(on_error)?;
+        let (n1, n2) = (to_num(s1), to_num(s2));
+
+        to_adjacency.entry(n1).or_insert_with(Vec::new).push(n2);
+        to_adjacency.entry(n2).or_insert_with(Vec::new).push(n1);
+
+        if s1.starts_with('t') {
+            with_t.push(n1)?;
+        }
+        if s2.starts_with('t') {
+            with_t.push(n2)?;
+        }
+    }
+
+    let mut already_considered = HashSet::new();
+    let mut result = 0;
+    let slice = with_t.slice_mut();
+    slice.sort_unstable();
+    let mut last = u16::MAX;
+    for n in slice {
+        if *n != last {
+            let adjacency_list = to_adjacency.get(n).unwrap();
+            for (i, x) in adjacency_list.iter().enumerate() {
+                for (j, y) in adjacency_list.iter().enumerate().skip(i + 1) {
+                    if to_adjacency.get(x).unwrap().iter().any(|e| e == y) {
+                        let mut aa = [*n, *x, *y];
+                        aa.sort_unstable();
+                        if already_considered.insert(aa) {
+                            result += 1;
+                        }
+                    }
+                }
+            }
+            last = *n;
+        }
+    }
+
+    Ok(result)
+}
+
+fn to_num(p: &str) -> u16 {
+    let p = p.as_bytes();
+    u16::from(p[0] - b'a') + 29 * u16::from(p[1] - b'a')
 }
 
 #[test]
 pub fn tests() {
     use crate::input::{test_part_one_no_allocations, test_part_two_no_allocations};
 
-    let test_input = "";
-    test_part_one_no_allocations!(test_input => 0);
-    test_part_two_no_allocations!(test_input => 0);
+    let test_input = "kh-tc
+qp-kh
+de-cg
+ka-co
+yn-aq
+qp-ub
+cg-tb
+vc-aq
+tb-ka
+wh-tc
+yn-cg
+kh-ub
+ta-co
+de-co
+tc-td
+tb-wq
+wh-td
+ta-ka
+td-qp
+aq-cg
+wq-ub
+ub-vc
+de-ta
+wq-aq
+wq-vc
+wh-yn
+ka-de
+kh-ta
+co-tc
+wh-qp
+tb-vc
+td-yn";
+    test_part_one_no_allocations!(test_input => 7);
+    //test_part_two_no_allocations!(test_input => 0);
 
     let real_input = include_str!("day23_input.txt");
-    test_part_one_no_allocations!(real_input => 0);
-    test_part_two_no_allocations!(real_input => 0);
+    test_part_one_no_allocations!(real_input => 1175);
+    //test_part_two_no_allocations!(real_input => 0);
 }