二分查找

datas必须是有序列表

public static int search(Integer[] datas,int dest){
    int start = 0;
    int end = datas.length -1 ;

    while(start <= end) {
        int middle = (end + start) >>> 1;
        if(dest == datas[middle]) {
            return middle;
        } else if(dest < datas[middle]) {
            end = middle - 1;
        } else if(dest > datas[middle]) {
            start = middle + 1;
        }
    }
    return -1;
}