while(l < r)
{
    int mid = l + r >> 1;
    if(up[mid] < target)
        l = mid + 1;
    else
        r = mid;
}
//递增序列找大等target
//多个target得到下标最小



while(l < r)
{
    int mid = l + r + 1 >> 1;
    if(up[mid] <= target)
        l = mid;
    else
        r = mid - 1;
}
//递增序列找小等target
//多个target得到下标最大



while(l < r)
{
    int mid = l + r >> 1;
    if(down[mid] > target)
        l = mid + 1;
    else
        r = mid;
}
//递减序列找小等target
//多个target得到下标最小



while(l < r)
{
    int mid = l + r + 1 >> 1;
    if(down[mid] >= target)
        l = mid;
    else
        r = mid - 1;
}
//递减序列找大等target
//多个target得到下标最大