Creating rural jobs is on everyone's to-do list, from the government to the U-N to aid groups.
VOA: standard.2010.03.30
What I am going to do now is I am going to multiply by N Avogadro and then add Born repulsion.
我接下来要做的是,将其乘以阿伏加德罗常数,再加入Born的排斥作用。
n So I've got to do n things n times.
所以就是做n次。
What does the U.N.plan to do with the data it has gathered now?
VOA: standard.2010.07.07
For n = --now I'm going to do n = 100.
对于n=...我假设n=100
So, the first thing we do is put two electrons between h and c, and then two electrons between c and n.
那么,我们先在氢和碳之间放两个电子,然后在碳和氮之间再放两个电子。
Now, it's kind of a cyclical argument here because how do you sort the left half of N elements?
在这儿有点循环的意思,那么如何对N个元素中的左半部分进行排序呢?
He constantly warns his son, who was kind of an n'er do well, that, "You better work hard, " Or, "You better work a little harder and pay more attention to what you're doing.
他不断提醒那一事无成的儿子,"你要加倍用功,哪怕只是稍微用点心,对你做的事要更上心
I could do this. I could call this n equals one, the fundamental frequency.
我可以这样做,我将n等于,基频。
Ah, n times, because for each value of i, I'm going to do that m thing, n*m so that is, close to what you said, right?
因此这就和你说的差不多了对不对?,这个问题的复杂度为,让我写下来,是-对不对,是?
Given the code up there, if I want to move a tower of size n, what do I have to do?
鉴于这里的代码,如果我想移动N个圆盘,我该怎么做?
So, let's, for example, look at nitrogen. So n 2, we can do the chart here in green, so it's the green dotted line, and what we see is that we have now defined this energy as where the 2 nitrogen atoms are separated.
那么,让我们举个例子,看一下氮,那么氮分子,我们可以把它用绿色曲线画在这,这是绿色的虚线,可以看到,我们已经定义为零点能,当两个氮原子分离时。
At this point in the story, I now check while n is less than 1, what do I do?
在此时此刻,我现在在检查当n小于1是,我做什么?
So, the optimal thing to do if you live in a world like this n is to get n as large possible and you can reduce the standard deviation of the portfolio very much and there's no cost in terms of expected return.
如果现实中也这样简单的话,那么你就尽量增大,这样就能让投资组合的标准差,就会大大降低,从预期收益率的角度来看,这样做的成本是零。
If we can sort things, you know, we get this n log n behavior, and we got a n log n behavior overall. But can we actually do better in terms of searching.
如果我们可以排序,如你所知,我们有n,log,n级别的算法,并且我有一个整体的n,log,n级别的算法,但是我们在搜索方面可以做的更好吗?
printf So thus far, the things I put David between quotes are just simple things like David or David backslash N, but what if I want to do call my self David in quotes, right?
像我们前面提到的,我们把要显示的东西放在双引号之间,譬如,或,David反斜杠n,但是如果我自己的名字本来就叫,“David“
So instead you'd have to maybe if you start with wavelength, go over there, and then figure out velocity and do something more like kinetic energy equals 1/2 n b squared to get there.
这时你要先从波长开始,到这,然后算出速度,然后像动能等于1/2nb平方得到这。
All right, I want to do one more at homonuclear example here, and this is n 2.
好的,我想要再讲一个同核的例子,这就是N2。
But that merging process only takes N steps, N*log N so that's N times log of N. Now, it's a little tricky to reason through this perhaps the first time, let's just take a very simple example and see if we can do a little sanity check here.
但这个合并过程只需要N步,所以时间复杂度是,第一次对此进行推论可能会有点儿棘手,我们举一个简单的例子,看看我们能否做一些完整性的检查。
So it feels a little backward mentally perhaps, 1 but this is saying, "do this block of code as long as n is less than 1."
所以它感觉可能有点迟缓,但是它指明,“只要n小于,执行这段代码“
In the linear case, meaning in the unsorted case what's the complexity of this? k times n, right? Order n to do the search, and I've got to do it k times, so this would be k times n.
复杂度是多少?k的n次方,对吧?,在序列n中做搜索,要做k次,所以是k的n次方次,如果先排序后搜索。
How do I rea-- replace the expression FOR t of n minus 1? Substitute it in again.
我们怎么来代替t这个表达式呢?,再来替换掉它,t等于。
So what we'll do is this problem here, which is let's calculate out what the wavelength of radiation n would be emitted from a hydrogen atom if we start at the n equals 3 level and we go down to the n equals 2 level.
我们来做这个问题,让我们来计算一下,从n等于3到,等于2能级氢原子辐射的波长是多少。
So we know that we can relate to z effective to the actual energy level of each of those orbitals, and we can do that using this equation here where it's negative z effective squared r h over n squared, we're going to see that again and again.
我们知道我们可以将有效电荷量与,每个轨道的实际能级联系起来,我们可以使用方程去解它,乘以RH除以n的平方,它等于负的有效电荷量的平方,我们将会一次又一次的看到它。
If it doesn't say anything else we do mean n equals 1.
如果没有别的条件我们都指n等于。
So this code is identical functionally nonswitch c to the last implementation we saw, nonswitch.c, but I'm just ever-more emphatically saying, "In case 1," that is when n equals 1 -- or when case 2 applies -- when n equals 2 or when n equals 3 do what?
所以这些代码到最后的实现上,功能是,完全相同的,但是我想要再次强调一下,“在case,1“,那是当n等于1时1,或者当case,2适用-,当n等于2或者当n等于3,它将做什么?
And the last thing we can think about is how do we name this n h bond, and again, we just name it based on it symmetry.
最后我们要讨论的是,如何命名这个NH键,同样,我们基于它的对称性命名它。
So if we go to the ground state, what you see is we're at that lowest energy level, and we only have one possibility for an orbital, because when n equals 1, that's all we can do.
如果我们在基态上,你可以看到,我们在能量最低的态上,只有一种,可能的轨道,因为n等于1,只有这种可能。
So I always have to do a merge of n elements.
所以我始终需要做n个元素的合并。
I could still do the linear case, which is order n or I could say, look, take the list, let's sort it and then search it. But in that case we said well to sort it was going to take n log n time, assuming I can do that.
我仍然可以做O的线性搜索,或者也可以以这个列表为例,我们先将其进行排序,然后再进行查找,但是在这种情况下,要花费n,log,n的时间去对其进行排序。
应用推荐