Updated Array Rotation problems

kowshikb · Mar 19, 2019 · 60d84d6 · 60d84d6
1 parent 47f5dd9
commit 60d84d6
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Showing 3 changed files with 12 additions and 21 deletions.
diff --git a/Cracking the Coding Interview/Data Structures/Arrays - Left Rotation/Solution.java b/Cracking the Coding Interview/Data Structures/Arrays - Left Rotation/Solution.java
@@ -32,15 +32,12 @@ public static void main(String[] args) {
     }
 
     /* Reverses array from "start" to "end" inclusive */
-    private static void reverse(int [] array, int start, int end) {
-        if (array == null || start < 0 || start >= array.length || 
-            end < 0 || end >= array.length || start >= end) {
+    private static void reverse(int[] array, int start, int end) {
+        if (array == null || start < 0 || start >= array.length || end < 0 || end >= array.length) {
             return;
         }
-        int mid = (start + end) / 2;
-        for (int i = start; i <= mid; i++) {
-            int offset = i - start;
-            swap(array, start + offset, end - offset);
+        while (start < end) {
+            swap(array, start++, end--);
         }
     }
 

diff --git a/Data Structures/Arrays/Left Rotation/Solution.java b/Data Structures/Arrays/Left Rotation/Solution.java
@@ -32,15 +32,12 @@ public static void main(String[] args) {
     }
 
     /* Reverses array from "start" to "end" inclusive */
-    private static void reverse(int [] array, int start, int end) {
-        if (array == null || start < 0 || start >= array.length || 
-            end < 0 || end >= array.length || start >= end) {
+    private static void reverse(int[] array, int start, int end) {
+        if (array == null || start < 0 || start >= array.length || end < 0 || end >= array.length) {
             return;
         }
-        int mid = (start + end) / 2;
-        for (int i = start; i <= mid; i++) {
-            int offset = i - start;
-            swap(array, start + offset, end - offset);
+        while (start < end) {
+            swap(array, start++, end--);
         }
     }
 

diff --git a/General Programming/Basic Programming/Circular Array Rotation/Solution.java b/General Programming/Basic Programming/Circular Array Rotation/Solution.java
@@ -34,15 +34,12 @@ public static void main(String[] args) {
     }
 
     /* Reverses array from "start" to "end" inclusive */
-    private static void reverse(int [] array, int start, int end) {
-        if (array == null || start < 0 || start >= array.length || 
-            end < 0 || end >= array.length || start >= end) {
+    private static void reverse(int[] array, int start, int end) {
+        if (array == null || start < 0 || start >= array.length || end < 0 || end >= array.length) {
             return;
         }
-        int mid = (start + end) / 2;
-        for (int i = start; i <= mid; i++) {
-            int offset = i - start;
-            swap(array, start + offset, end - offset);
+        while (start < end) {
+            swap(array, start++, end--);
         }
     }