perf(02/2024): simplify item removal from vector and improve performance

manhunto · Dec 2, 2024 · ee2fac0 · ee2fac0
1 parent 9a92130
commit ee2fac0
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Showing 2 changed files with 17 additions and 22 deletions.
diff --git a/readme.md b/readme.md
@@ -12,7 +12,7 @@
 | Day                                                          | Solved | Part 1 time (ms) | Part 2 time (ms) |
 |--------------------------------------------------------------|:------:|-----------------:|-----------------:|
 | [Day 1: Historian Hysteria](src/solutions/year2024/day01.rs) |   ⭐⭐   |            0.221 |            0.219 |
-| [Day 2: Red-Nosed Reports](src/solutions/year2024/day02.rs)  |   ⭐⭐   |            0.508 |            1.228 |
+| [Day 2: Red-Nosed Reports](src/solutions/year2024/day02.rs)  |   ⭐⭐   |            0.508 |            0.853 |
 
 # 2023
 

diff --git a/src/solutions/year2024/day02.rs b/src/solutions/year2024/day02.rs
@@ -5,19 +5,15 @@ pub struct Day02;
 
 impl Solution for Day02 {
     fn part_one(&self, input: &str) -> String {
-        let input = self.parse(input);
-
-        input
+        self.parse(input)
             .iter()
             .filter(|report| self.is_report_safe(report))
             .count()
             .to_string()
     }
 
     fn part_two(&self, input: &str) -> String {
-        let input = self.parse(input);
-
-        input
+        self.parse(input)
             .iter()
             .filter(|report| {
                 let result = self.is_report_safe(report);
@@ -27,12 +23,10 @@ impl Solution for Day02 {
 
                 (0..report.len())
                     .map(|i| {
-                        report
-                            .iter()
-                            .enumerate()
-                            .filter(|&(index, _)| index != i)
-                            .map(|(_, &value)| value)
-                            .collect()
+                        let mut new: Vec<i32> = report.to_vec();
+                        let _ = new.remove(i);
+
+                        new
                     })
                     .any(|report| self.is_report_safe(&report))
             })
@@ -53,7 +47,7 @@ impl Day02 {
             .collect()
     }
 
-    fn is_report_safe(&self, report: &Vec<i32>) -> bool {
+    fn is_report_safe(&self, report: &[i32]) -> bool {
         let mut state: Option<Ordering> = None;
 
         for i in 0..report.len() - 1 {
@@ -65,16 +59,17 @@ impl Day02 {
             }
 
             let current_state = first.cmp(second);
-            if let Some(inner_state) = state {
-                if inner_state == Ordering::Equal {
-                    return false;
-                }
-                if inner_state != current_state {
-                    return false;
-                }
-            } else {
+            if current_state == Ordering::Equal {
+                return false;
+            }
+
+            if state.is_none() {
                 state = Some(current_state);
             }
+
+            if state.is_some_and(|inner| inner != current_state) {
+                return false;
+            }
         }
 
         true