From 6f7bb5920edf8a7f21cea0dd484040b65bfacdde Mon Sep 17 00:00:00 2001
From: Danny van der Sluijs <danny.van.der.sluijs@infi.nl>
Date: Fri, 5 May 2023 19:24:41 +0200
Subject: [PATCH] perf: Backport v5 performance improvements onto v4.0.4
 (3461e3f)

---
 ...ientLongestCommonSubsequenceCalculator.php |  7 +++++-
 ...ientLongestCommonSubsequenceCalculator.php | 24 ++++++++++++++-----
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/MemoryEfficientLongestCommonSubsequenceCalculator.php b/src/MemoryEfficientLongestCommonSubsequenceCalculator.php
index 0b626eaf..489113b6 100644
--- a/src/MemoryEfficientLongestCommonSubsequenceCalculator.php
+++ b/src/MemoryEfficientLongestCommonSubsequenceCalculator.php
@@ -78,7 +78,12 @@ private function length(array $from, array $to): array
                 if ($from[$i] === $to[$j]) {
                     $current[$j + 1] = $prev[$j] + 1;
                 } else {
-                    $current[$j + 1] = max($current[$j], $prev[$j + 1]);
+                    // don't use max() to avoid function call overhead
+                    if ($current[$j] > $prev[$j + 1]) {
+                        $current[$j + 1] = $current[$j];
+                    } else {
+                        $current[$j + 1] = $prev[$j + 1];
+                    }
                 }
             }
         }
diff --git a/src/TimeEfficientLongestCommonSubsequenceCalculator.php b/src/TimeEfficientLongestCommonSubsequenceCalculator.php
index fd19cac7..4e8d951d 100644
--- a/src/TimeEfficientLongestCommonSubsequenceCalculator.php
+++ b/src/TimeEfficientLongestCommonSubsequenceCalculator.php
@@ -37,12 +37,24 @@ public function calculate(array $from, array $to): array
 
         for ($i = 1; $i <= $fromLength; ++$i) {
             for ($j = 1; $j <= $toLength; ++$j) {
-                $o          = ($j * $width) + $i;
-                $matrix[$o] = max(
-                    $matrix[$o - 1],
-                    $matrix[$o - $width],
-                    $from[$i - 1] === $to[$j - 1] ? $matrix[$o - $width - 1] + 1 : 0
-                );
+                $o = ($j * $width) + $i;
+
+                // don't use max() to avoid function call overhead
+                $firstOrLast = $from[$i - 1] === $to[$j - 1] ? $matrix[$o - $width - 1] + 1 : 0;
+
+                if ($matrix[$o - 1] > $matrix[$o - $width]) {
+                    if ($firstOrLast > $matrix[$o - 1]) {
+                        $matrix[$o] = $firstOrLast;
+                    } else {
+                        $matrix[$o] = $matrix[$o - 1];
+                    }
+                } else {
+                    if ($firstOrLast > $matrix[$o - $width]) {
+                        $matrix[$o] = $firstOrLast;
+                    } else {
+                        $matrix[$o] = $matrix[$o - $width];
+                    }
+                }
             }
         }