search - fibonacci search

Posted 2022-12-03 小马识图

#include "stdio.h"
#include "string.h"
#include "malloc.h"  

#define MAX_LIST 50

typedef struct _SqList 
    int data[MAX_LIST];
    int length;
SqList;

//The key difference between Fibonacci search and binary search 
//is how the anchor point is determined.
bool FibonacciSearch( SqList* L, int key, int& loc )

    static int F[] =  0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55 ;
    int low = 0;
    int high = L->length - 1;
    int mid;

    int l = L->length;
    int k = 0;
    for( ; F[k] < L->length; k++ );

    int *buf = L->data;

    //padding with duplicate numbers if necessary
    if( F[k] > MAX_LIST )
    
        buf = (int*)malloc( F[k]*sizeof(buf[0]) );
        memcpy( buf, L->data, L->length*sizeof(buf[0]) );
       
    for( ; l < F[k]; l++ )
        buf[l] = L->data[high];

    l = -1;
    high = F[k] - 1;

    while( k > 0 && low <= high ) 
    
        mid = low + F[k-1];

        if( key < buf[mid] )
        
            high = mid - 1;
            k = k - 1;
        
        else if( key > buf[mid] )
        
            low = mid + 1;
            k = k -2;
        
        else
        
            if( mid < L->length )
                l = mid;
            else
                l = L->length - 1;
            break;
        
       

    if( buf != L->data ) free(buf);
    return ( loc = l ) != -1;;


int main()

    SqList d;
    int intarr[] = 1,10,23,48,65,67,78,79,98,100;
    memcpy( d.data, intarr, sizeof(intarr));
    d.length = sizeof(intarr)/sizeof(int);  
    int index = 0;
    for( ; index < d.length; index++ )
        printf(" %d", d.data[index] );
    int key = 100;
    printf("\\nfibonacci search %d...\\n", key);
    FibonacciSearch( &d, key, index );
    printf("%d is at position %d\\n", key, index);
    printf("\\n");
    return 0;