Advent 2025 Day 6 Part 2

advent_of_code_2025/src/day6/part2.rs

@@ -1,34 +1,50 @@
 pub fn solve(input: &str) {
-    let lines = input.lines().collect::<Vec<_>>();
+    let transposed = input.lines().map(|line| line.as_bytes()).collect::<Vec<_>>();
+    let mut lines = Vec::new();
 
-    let rows = lines[..(lines.len() - 1)].iter().map(|line| {
+    for idx in 0..transposed[0].len() {
-        line.split(" ").filter(|str| !str.is_empty()).map(|num| { num.parse::<u64>().unwrap() }).collect::<Vec<_>>()
+        let mut line = Vec::with_capacity(transposed.len());
+        for row in transposed.iter() {
+            line.push(row[idx]);
+        }
+        lines.push(line);
+    }
+
+    let problems = lines.split(|line| {
+        line[..] == [32].repeat(line.len())
     }).collect::<Vec<_>>();
 
-    let operators = lines.last().unwrap().bytes().filter(|b| *b != b' ').collect::<Vec<_>>();
+    let mut sum_of_results = 0;
-    
-    // println!("rows: {rows:?}");
-    // println!("operators: {operators:?}");
 
-    let mut sum_of_operations = 0;
+    for problem in problems {
-
+        let op = problem.first().unwrap().last().unwrap();
-    for (idx, operator) in operators.iter().enumerate() {
+        
-        if *operator == b'*' {
+        if *op == b'*' {
             let mut result = 1;
-            for row in rows.iter() {
+
-                result *= row[idx];
+            for line in problem.iter() {
+                let cleaned = line[..(line.len() - 1)].iter().filter(|byte| **byte != b' ').copied().collect::<Vec<_>>();
+                // println!("cleaned: {cleaned:?}");
+                let parsed = unsafe { str::from_utf8_unchecked(&cleaned) }.parse::<u64>().unwrap();
+                // println!("parsed: {}", parsed);
+                result *= parsed;
             }
-            // println!("row {idx} (*): {result}");
+            sum_of_results += result;
-            sum_of_operations += result;
+            // println!("result: {}", result);
         } else {
             let mut result = 0;
-            for row in rows.iter() {
+
-                result += row[idx];
+            for line in problem.iter() {
+                let cleaned = line[..(line.len() - 1)].iter().filter(|byte| **byte != b' ').copied().collect::<Vec<_>>();
+                // println!("cleaned: {cleaned:?}");
+                let parsed = unsafe { str::from_utf8_unchecked(&cleaned) }.parse::<u64>().unwrap();
+                // println!("parsed: {}", parsed);
+                result += parsed;
             }
-            // println!("row {idx} (+): {result}");
+            sum_of_results += result;
-            sum_of_operations += result;
+            // println!("result: {}", result);
         }
     }
 
-    println!("sum of operations: {sum_of_operations}");
+    println!("sum of operations: {sum_of_results}");
 }

advent_of_code_2025/src/main.rs

@@ -1,5 +1,5 @@
 use paste::paste;
 mod utility;
 
-solve_day!{2}
+solve_day!{6}
-// test_day!{2}
+// test_day!{6}