How to implement dichotomy in C language to find array elements

coldplay.xixi
Release: 2023-01-03 09:30:14
Original
5634 people have browsed it

C language dichotomy method to implement finding array elements: 1. Recursive algorithm, the code is [if(a[mid] == key) return mid]; 2. Non-recursive algorithm, the code is [while( left < right && a[mid] != key )].

How to implement dichotomy in C language to find array elements

The operating environment of this tutorial: windows7 system, c99 version, DELL G3 computer.

C language dichotomy method to implement finding array elements:

Recursive algorithm

#include<stdio.h>
//二分法实现数组查找
 
//
int recurbinary(int *a, int key, int low, int high)
{
    int mid;
    if(low > high)
        return -1;
    mid = (low + high)/2;
    if(a[mid] == key) return mid;
    else if(a[mid] > key)
         return recurbinary(a,key,low,mid -1);
    else
         return recurbinary(a,key,mid + 1,high);
 
}
Copy after login

Non-recursive algorithm

int binary( int *a, int key, int n )
{
    int left = 0, right = n - 1, mid = 0;
    mid = ( left + right ) / 2;
    while( left < right && a[mid] != key )
    {
        if( a[mid] < key ) {
            left = mid + 1;
        } else if( a[mid] > key ) {
            right = mid - 1;
        }
        mid = ( left + right ) / 2;
    }
    if( a[mid] == key )
        return mid;
    return -1;
}
 
int main(void)
{
int a[10] = {2,4,6,8,10,12,14,16,18,20},t,k,f;
scanf("%d",&t);
k = recurbinary(a,t,2,20);
f = binary(a,t,10);  //非递归算法
if(k == -1){
printf("不存在此数\n");
}else{
printf("%-5d是数组第%d个元素\n%-5d数组的第%d个元素",k,k+1,f,f+1);
}
 
return 0;
}
Copy after login

[Related learning recommendations: C language tutorial video]

The above is the detailed content of How to implement dichotomy in C language to find array elements. For more information, please follow other related articles on the PHP Chinese website!

Related labels:
source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn:Public welfare online PHP training,Help PHP learners grow quickly!