128 lines
4.4 KiB
C++
128 lines
4.4 KiB
C++
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// ***Cycle Sort***
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// This sorting algorithm is best suited for situations where memory write or swap operations are costly.
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// it is In-place and not stable
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#include<bits/stdc++.h>
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using namespace std;
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void cycleSort(int arr[], int size)
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{
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for(int cyclestart=0;cyclestart<size-1;cyclestart++){
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int item=arr[cyclestart];
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int pos=cyclestart;
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for(int i=cyclestart+1;i<size;i++) //count total no of item less then curr item in an array
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if(arr[i]<item)
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pos++;
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swap(item,arr[pos]); //swap item to it's correct position
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while(pos!=cyclestart){ // now we have to find the index of prev item which is presnt at pos and we keep doing this till pos!=cyclestart
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pos=cyclestart;
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for(int i=cyclestart+1;i<size;i++)
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if(arr[i]<item)
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pos++;
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swap(item,arr[pos]);
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}
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}
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}
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int main()
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{
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int arr[] = { 20,40,10,50,30 };
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int size = sizeof(arr) / sizeof(arr[0]);
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cycleSort(arr, size);
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for (int i = 0; i < size; i++)
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cout << arr[i] << " ";
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return 0;
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}
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/*
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Time Complexity : O(n2)
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Worst Case : O(n2)
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Average Case: O(n2)
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Best Case : O(n2)
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Explanation:-
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int arr[] = { 20,40,10,50,30};
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int size= 5;
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iteration 1:
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cyclestart=0;
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item = 20;
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pos = 0;
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for(int i=cyclestart+1;i<size;i++) //count total no of item less then 20 in a array to find correct index of 20 in array
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if(arr[i]<item)
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pos++;
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pos=1 //index of 20 is 1(pos) in a array
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swap(item,arr[pos]); //swap 20(item) with item present at index pos i.e 40.
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item=40;
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pos=1;
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//Now we have to count item less then 40 in array and swap that item with updated pos
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pos=3
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swap(40,arr[3]) // swap 40 with 50
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item=50;
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pos=3
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//Now we have to count item less then 50 in array and swap that item with updated pos
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pos=4
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swap(50,arr[4]) //swap 50 with 30
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item=30;
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pos=4;
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//Now we have to count item less then 30 in array and swap that item with updated pos
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pos=2;
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swap(30,arr[2]) //swap 30 with 10
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item=10;
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pos=2;
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//Now we have to count item less then 10 in array and swap that item with updated pos
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pos=0;
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swap(10,arr[0]) //place 10 at 0index
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pos=cyclestart while-loop terminate
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Updated array after iterative 1 array = {10,20,30,40,50};
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iteration 2:
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cyclestart=1;
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item = 20;
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pos = 1;
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for(int i=cyclestart+1;i<size;i++) //count total no of item less then 20 in a array to find correct index of 20 in array
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if(arr[i]<item
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pos++;
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pos=1
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swap(item,arr[pos]);
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pos=cyclestart while-loop terminate
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iteration 3:
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cyclestart=2;
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item = 30;
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pos = 2;
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for(int i=cyclestart+1;i<size;i++) //count total no of item less then 30 in a array to find correct index of 20 in array
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if(arr[i]<item)
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pos++;
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pos=2
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swap(item,arr[pos]);
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pos=cyclestart while-loop terminate
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iteration 4:
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cyclestart=3;
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item = 40;
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pos = 3;
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for(int i=cyclestart+1;i<size;i++) //count total no of item less then 40 in a array to find correct index of 20 in array
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if(arr[i]<item)
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pos++;
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pos=3
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swap(item,arr[pos]);
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pos=cyclestart while-loop terminate
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*/
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