[solved] Correctness and the Loop Invariant

Correctness and the Loop Invariant.php

@@ -0,0 +1,36 @@
+<?php
+/**
+ * @author: syed ashraf ullah
+ * date: 22/04/2020
+ * problem: https://www.hackerrank.com/challenges/correctness-invariant/problem
+ */
+
+function insertionSort(&$arr){
+   for($i=0;$i<count($arr);$i++){
+      $val = $arr[$i];
+      $j = $i-1;
+      while($j>=0 && $arr[$j] > $val){
+         $arr[$j+1] = $arr[$j];
+         $j--;
+      }
+      $arr[$j+1] = $val;
+   }
+}
+/**
+ * Sample #1
+ */
+// $arr = array(7, 4, 3, 5, 6, 2);
+// insertionSort($arr);
+// foreach($arr as $value) {
+//   print $value." ";
+// }
+// return;
+$handle = fopen ("php://stdin","r");
+$t = fgets($handle);
+$arr = explode(' ', fgets($handle));
+
+insertionSort($arr);
+foreach($arr as $value) {
+  print $value." ";
+}
+?>

Insertion Sort - Part 2.php

@@ -11,15 +11,15 @@ function insertionSort1($n, $arr)
     while (++$i < $n) {
 
         $k = $i;
-
+        $val = $arr[$k];
+
         // Sort from current index
-        while (--$k >= 0 && $arr[$k] > $arr[$k+1]) {
-            $copy = $arr[$k];
-            $arr[$k] = $arr[$k+1];
-
-            $arr[$k+1] = $copy;
+        while (--$k >= 0 && $val < $arr[$k]) {
+            $arr[$k+1] = $arr[$k];    
         }
 
+        $arr[$k+1] = $val;
+
         // Print current array
         foreach ($arr as $value) {
             echo $value.' ';
@@ -36,16 +36,16 @@ function insertionSort1($n, $arr)
 /**
  * Sample input #1
  */
-// $n = 6;
-// $arr = array(1, 4, 3, 5, 6, 2);
+$n = 6;
+$arr = array(1, 4, 3, 5, 6, 2);
 
 /**
  * Sample input #2
  */
 // $n = 7;
 // $arr = array(3, 4, 7, 5, 6, 2, 1);
-// insertionSort1($n, $arr);
-// return;
+insertionSort1($n, $arr);
+return;
 
 $stdin = fopen("php://stdin", "r");