From f16175eeee3b4709876207a776f93398b076d01f Mon Sep 17 00:00:00 2001
From: Ishan Jain <contact@ishanjain.me>
Date: Thu, 11 Jan 2024 03:34:28 +0530
Subject: [PATCH] minor optimizations

---
 src/main.rs | 51 ++++++++++++++++++++++++++-------------------------
 1 file changed, 26 insertions(+), 25 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index f04ee14..8454c85 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -24,12 +24,12 @@ fn main() {
             continue;
         }
 
-        let loc = if line[l - 4] == b';' {
-            l - 4
+        let loc = if line[l - 6] == b';' {
+            l - 6
         } else if line[l - 5] == b';' {
             l - 5
-        } else if line[l - 6] == b';' {
-            l - 6
+        } else if line[l - 4] == b';' {
+            l - 4
         } else {
             unreachable!();
         };
@@ -39,34 +39,34 @@ fn main() {
 
         let val = parse_float(val);
 
-        let (min, sum, max, counter) =
-            map.entry(city)
-                .or_insert((std::f32::MAX, 0.0, std::f32::MIN, 0));
+        let (min, sum, max, counter) = map
+            .entry(city)
+            .or_insert_with(|| (std::i16::MAX, 0, std::i16::MIN, 0));
 
         *min = val.min(*min);
         *max = val.max(*max);
         *counter += 1;
-        *sum += val;
+        *sum += val as i32;
     }
 
     let t2_elapsed = t2.elapsed();
 
     let t3 = Instant::now();
 
-    let mut list: Vec<(&[u8], (f32, f32, f32, usize))> = map.into_iter().collect();
+    let mut list: Vec<(&[u8], (i16, i32, i16, usize))> = map.into_iter().collect();
     list.sort_unstable_by(|(a, _), (b, _)| a.cmp(b));
 
     let mut output = String::new();
 
     let l = list.len();
 
-    for (i, (city, (min, mean, max, counter))) in list.into_iter().enumerate() {
+    for (i, (city, (min, sum, max, counter))) in list.into_iter().enumerate() {
         output.push_str(&format!(
             "{}={:.1}/{:.1}/{:.1}{}",
             String::from_utf8_lossy(city),
-            min,
-            mean / counter as f32,
-            max,
+            (min as f32 / 10.0),
+            (sum as f32 / 10.0) / counter as f32,
+            (max as f32 / 10.0),
             if i == l - 1 { "" } else { ", " }
         ));
     }
@@ -82,30 +82,31 @@ fn main() {
 }
 
 #[inline]
-fn parse_float(b: &[u8]) -> f32 {
+fn parse_float(b: &[u8]) -> i16 {
     let l = b.len();
-    let mut num: i32 = 0;
+    let mut num: i16 = 0;
     let mut is_negative = false;
 
-    for &c in b.iter().take_while(|&&x| x != b'.') {
-        match c {
+    let mut i = 0;
+    while unsafe { *b.get_unchecked(i) } != b'.' {
+        match unsafe { *b.get_unchecked(i) } {
             v @ b'0'..=b'9' => {
                 num *= 10;
-                num += (v - b'0') as i32;
+                num += (v - b'0') as i16;
             }
             b'-' => is_negative = true,
-            b'.' => continue,
-
-            _ => unreachable!(),
+            b'.' => break,
+            _ => (),
         }
+        i += 1;
     }
 
-    let mut num = num as f32;
+    num *= 10;
+    num += (b[l - 1] - b'0') as i16;
 
-    num += 0.1 * (b[l - 1] - b'0') as f32;
     if is_negative {
-        num *= -1.0;
+        num *= -1;
     }
 
-    num * 10.0 / 10.0
+    num
 }