Milishparsai007 cycle sort

16_FirstContribution/SORTING/CycleSort.java

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+//What is Cycle sort 
+//When we are given numbers from 1 to N (not necessarily exactly from 1 to N) we use cycle sort.
+//It sorts the entire array in one single pass.
+//The basic idea behind cycle sort is the sorted array will contain elements on their correct index.
+//For eg. - elements from 1 to 5 will be on index 0 to 4 in the sorted array.
+//Advantages are :- It sorts the array in-place and does not require additional memory for temporary variables.
+
+//Here is the link for leetcode question which is solved using cycle sort.
+//https://leetcode.com/problems/missing-number/
+
+//Here is the link for leetcode question which is solved using cycle sort.
+//https://leetcode.com/problems/first-missing-positive/description/
+
+
+public class CycleSort {
+
+    public static void swap(int arr[],int start,int end)
+    {
+        int temp=arr[start];
+        arr[start]=arr[end];
+        arr[end]=temp;
+    }
+
+    public static void cycleSort(int arr[])
+    {
+        int i=0;
+        while(i<arr.length)
+        {
+            int correctIndex=arr[i]-1;  //correctIndex is the index that has the value equal to correctIndex-1.
+            if(arr[i]==arr[correctIndex]) //if value of index i is equal to the value at correctIndex i.e., equal to (value of index i) -1.
+                //index number (arr[i]) should contain (arr[i]-1)
+            {
+                i++;
+            }
+            else
+            {
+                swap(arr,i,correctIndex);
+            }
+        }
+
+        for(int x:arr)
+        {
+            System.out.print(x+" ");
+        }
+    }
+
+    public static void main(String[] args) {
+        int arr[]={3,5,2,1,4};
+        cycleSort(arr);
+    }
+}