public class Search {

    /* * 顺序查找,返回关键字在数组中第一次出现的位置, 没找到返回-1 */
    public static int searchSeq(int[] a, int key){

        for(int i = 0; i < a.length; i++){
            if (a[i] == key){
                return i + 1;
            }
        }
        return -1;
    }

    /* * 折半查找，要求数组是有序排列的（从小到大） * */

    public static int searchBin(int[] a, int key){
        int low = 0, high = a.length - 1;
        while (low <= high){
            int mid = (low+high)/2;
            if (a[mid] == key){
                return mid+1;
            }else if(a[mid] > key){ //如果中间值大于查找值，那么将高位标记减一
                high = mid - 1;
            }else{                  //如果中间值小于查找值，将低位标记加一
                low = mid + 1;
            }
        }
        return -1;
    }

    public static void main(String[] args) {
// int[] seq = {2, 4, 5, 6, 8, 10, 3};
// int[] bin = {1, 2, 3, 4, 5, 6, 7, 8};
// System.out.println(searchSeq(seq, 6));
// System.out.println(searchBin(bin, 8));

    }

}