二分查找[递归+循环]

使用递归实现二分查找

 

 1 #include <stdio.h>
 2 
 3 void binary_sort(int a[], int num, int head, int tail)
 4 {
 5     if (head <= tail) {
 6         int middle = (head+tail)/2;
 7         if (num>a[middle])
 8             binary_sort(a, num, middle+1, tail);
 9         else if (num<a[middle])
10             binary_sort(a, num, head, middle-1);
11         else if (num == a[middle])
12             printf("找到a[%d]=%d", middle, a[middle]);
13     }
14     else {
15         printf("未找到%d", num);
16     }
17 }
18 
19 int main()
20 {
21     int a[15]={1,2,3,4,5,6,7,8,9,10,11,12,13,14,16};
22     int num=18;
23     int head = 0;
24     int tail = 14;
25     binary_sort(a, num, head, tail);
26 
27     return 0;
28 }

  

使用循环实现二分查找

 1 #include <stdio.h>
 2 
 3 void binary_sort(int a[], int num, int head, int tail)
 4 {
 5     int middle = (head+tail)/2;
 6     while (head <= tail) {
 7         if (num > a[middle]) {
 8             head = middle+1;
 9             middle = (head+tail)/2;
10         } else if (num < a[middle]) {
11             tail = middle-1;
12             middle = (head+tail)/2;
13         } else {
14             printf("找到a[%d]=%d", middle, a[middle]);
15             return ;
16         }
17     }
18     printf("未找到%d", num);
19 }
20 
21 int main()
22 {
23     int a[15]={1,2,3,4,5,6,7,8,9,10,11,12,13,14,16};
24     int num=18;
25     int head = 0;
26     int tail = 14;
27     binary_sort(a, num, head, tail);
28 
29     return 0;
30 }

 

posted @ 2014-12-22 13:14  IFPELSET  阅读(132)  评论(0)  编辑  收藏  举报