From 5d140669a2931ef487e6a820a25640d3928a768b Mon Sep 17 00:00:00 2001
From: yangmin <iyoungm@163.com>
Date: Thu, 25 Oct 2018 16:08:13 +0800
Subject: [PATCH 1/2] php 12_merge_sort

---
 php/12_sort/mergeSort.php | 63 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 php/12_sort/mergeSort.php

diff --git a/php/12_sort/mergeSort.php b/php/12_sort/mergeSort.php
new file mode 100644
index 0000000..e32ff52
--- /dev/null
+++ b/php/12_sort/mergeSort.php
@@ -0,0 +1,63 @@
+<?php
+
+    $arr = [1, 5, 8, 6, 7, 9];
+    $length = count($arr);
+
+    $p = 0;
+    $r = $length - 1;
+
+    $result = $this->mergeSort($arr, $p, $r);
+
+    var_dump($result);
+
+
+//递归调用,分解数组
+function mergeSort(array $arr, $p, $r)
+{
+    if ($p >= $r) {
+        return [$arr[$r]];
+    }
+    $q = (int)(($p + $r) / 2);
+
+    $left = $this->mergeSort($arr, $p, $q);
+    $right = $this->mergeSort($arr, $q + 1, $r);
+    return $this->merge($left, $right);
+}
+
+//合并
+function merge(array $left, array $right)
+{
+    $tmp = [];
+
+    $i = 0;
+
+    $j = 0;
+
+    $leftLength = count($left);
+
+    $rightLength = count($right);
+
+    do {
+        if ($left[$i] <= $right[$j]) {
+            $tmp[] = $left[$i++];
+        } else {
+            $tmp[] = $right[$j++];
+        }
+
+    } while ($i < $leftLength && $j < $rightLength);
+
+    $start = $i;
+    $end = $leftLength;
+
+    if ($j < $rightLength) {
+        $start = $j;
+        $end = $rightLength;
+    }
+
+    for (; $start < $end; $start++) {
+        $tmp[] = $right[$start];
+    }
+
+    return $tmp;
+
+}
\ No newline at end of file

From bfb3dd581f76815a7723ba7c11fa1d19859dcd3e Mon Sep 17 00:00:00 2001
From: yangmin <iyoungm@163.com>
Date: Thu, 25 Oct 2018 17:03:39 +0800
Subject: [PATCH 2/2] fix mergeSort

---
 php/12_sort/mergeSort.php | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/php/12_sort/mergeSort.php b/php/12_sort/mergeSort.php
index e32ff52..6d2e876 100644
--- a/php/12_sort/mergeSort.php
+++ b/php/12_sort/mergeSort.php
@@ -1,6 +1,6 @@
 <?php
 
-    $arr = [1, 5, 8, 6, 7, 9];
+    $arr = [4, 5, 6, 1, 3, 2];
     $length = count($arr);
 
     $p = 0;
@@ -46,16 +46,19 @@ function merge(array $left, array $right)
 
     } while ($i < $leftLength && $j < $rightLength);
 
+
     $start = $i;
     $end = $leftLength;
+    $copyArr = $left;
 
     if ($j < $rightLength) {
         $start = $j;
         $end = $rightLength;
+        $copyArr = $right;
     }
 
     for (; $start < $end; $start++) {
-        $tmp[] = $right[$start];
+        $tmp[] = $copyArr[$start];
     }
 
     return $tmp;