//二分法查找: |
//a是查找的数组,二分法查找的前提条件是a数据的排序是有序的。key是待查找的变量,n是数组a的长度。 |
#include<stdio.h> |
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; |
} |
|
//调用: |
//查找数组b在数组a中的下标的位置(当a中不存在b中的数据时,用-1代替)。 |
int main() |
{ |
int a[] = {1,2,3,4,5,6,7,8,9,12,13,45,67,89,99,101,111,123,134,565,677}; |
int b[] = { 677, 1, 7, 11, 67 }; |
int i; |
int n=20; |
for ( i=0; i<n;i++) { |
printf ( "%d\n" , binary( a, b[i], sizeof (a)/ sizeof (a[0]))); |
} |
return 0; |
} |
by: 发表于:2018-05-28 15:25:26 顶(0) | 踩(1) 回复
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