From 91b64fbfc46ab8916eeffd038cb267726a9ec37f Mon Sep 17 00:00:00 2001
From: Kirisame <gensky377@gmail.com>
Date: Wed, 14 Feb 2024 22:45:44 +0900
Subject: [PATCH] perf: optimized space complexity

---
 src/sorting/quick_sort.rs | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/sorting/quick_sort.rs b/src/sorting/quick_sort.rs
index 9f47587dafa..102edc6337d 100644
--- a/src/sorting/quick_sort.rs
+++ b/src/sorting/quick_sort.rs
@@ -1,5 +1,3 @@
-use std::cmp::PartialOrd;
-
 pub fn partition<T: PartialOrd>(arr: &mut [T], lo: usize, hi: usize) -> usize {
     let pivot = hi;
     let mut i = lo;
@@ -25,13 +23,19 @@ pub fn partition<T: PartialOrd>(arr: &mut [T], lo: usize, hi: usize) -> usize {
     i
 }
 
-fn _quick_sort<T: Ord>(arr: &mut [T], lo: usize, hi: usize) {
-    if lo < hi {
-        let p = partition(arr, lo, hi);
-        if p > 0 {
-            _quick_sort(arr, lo, p - 1);
+fn _quick_sort<T: Ord>(arr: &mut [T], mut lo: usize, mut hi: usize) {
+    while lo < hi {
+        let pivot = partition(arr, lo, hi);
+
+        if pivot - lo < hi - pivot {
+            if pivot > 0 {
+                _quick_sort(arr, lo, pivot - 1);
+            }
+            lo = pivot + 1;
+        } else {
+            _quick_sort(arr, pivot + 1, hi);
+            hi = pivot - 1;
         }
-        _quick_sort(arr, p + 1, hi);
     }
 }