二分查找

发表于 | 分类于

二分查找的前提是，数组是有序数组，目标元素一定在数组中

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
static const int COUNT = 10;

int search(int arr[], int target)
{
    int left = 0;
    int right = COUNT - 1;
    int mid = (left+right)/2;
    
    while (1) {
        
        // 说明元素在右边
        if (target > arr[mid]) {
            left = mid + 1;
            mid = (left + right)/2;
            
        // 说明元素在左边
        }else if (target < arr[mid]) {
            right = mid - 1;
            mid = (left + right)/2;
            
        }else{
            // 一直到找到为止
            return mid;
        }
    }
}