C++ Programming Code Examples
C++ > Sorting Searching Code Examples
Search Sorted Sequence Using Divide and Conquer with the Aid of Fibonacci Numbers
/* Search Sorted Sequence Using Divide and Conquer with the Aid of Fibonacci Numbers
- It implements a Divide and Conquer approach using Fibonacci numbers.
- Using Fibonacci numbers we calculate mid of data array to search the data item.
- The time complexity is O(log(n)).
- Calculate the mid of the array.
- Divide the array into two sub-array.
- Compare the item with mid element and proceed accordingly.
- Exit.
C++ program to implement Fibonacci Search. */
#include<iostream>
using namespace std;
void FibonacciSearch(int *a, int start, int end, int *fab, int index, int item)
{
int i, mid;
// Assigning middle of the array using Fibonacci element.
mid = start+fab[index-2];
// Return if item found at mid index.
if(item == a[mid])
{
cout<<"\n item found at "<<mid<<" index.";
return;
}
// Return if item found at start index.
else if(item == a[start])
{
cout<<"\n item found at "<<start<<" index.";
return;
}
// Return if item found at end index.
else if(item == a[end])
{
cout<<"\n item found at "<<end<<" index.";
return;
}
// If mid becomes start or end of the sub-array then element not found.
else if(mid == start || mid == end)
{
cout<<"\nElement not found";
return;
}
// According to the item value choose the partion to proceed further.
else if(item > a[mid])
FibonacciSearch(a, mid, end, fab, index-1, item);
else
FibonacciSearch(a, start, mid, fab, index-2, item);
}
main()
{
int n, i, biter, fab[20], a[20]={2, 9, 19, 23, 25, 36, 39, 43, 49, 57, 59, 66, 69, 74, 75, 77, 88, 89, 96, 97};
char ch;
fab[0] = 0;
fab[1] = 1;
i = 1;
while(fab[i] < 20)
{
i++;
fab[i] = fab[i-1]+fab[i-2];
}
up:
cout<<"\nEnter the Element to be searched: ";
cin>>n;
// Implement Fibonacci search.
FibonacciSearch(a, 0, 19, fab, i, n);
// Ask user to enter choice for further searching.
cout<<"\n\n\tDo you want to search more...enter choice(y/n)?";
cin>>ch;
if(ch == 'y' || ch == 'Y')
goto up;
return 0;
}
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