基本的算法

防止忘记,以后把学到的算法都写在这里:

 

1.二分查找

 

 

int binsearch(int x, int v[], int n)
{
    int low = 0;
    int high = n - 1;
    int mid;

    while (low <= high) {
        mid = (low + high) / 2;

        if (x > v[mid])
            low = mid + 1;
        else if (x < v[mid])
            high = mid - 1;
        else   
            return mid; /* found match, 返回其位置 */
    }
    return -1;          /* no match 返回-1 */
}

/* 得到一个数量为n的不重复的随机数组 */
get_rand_array(int data[], int n)
{
    int i;
    
    bzero(data, n);/* set data into 0 */
    for (i = 0; i < n; i++) {
        while (search((num = get_rand()), data, i)) /* this num in data ? */
           ; /* skip */
        data[i] = num; /* save it into data */
    } 
}