字幕列表 影片播放 列印英文字幕 might I call on, say, two volunteers to kick us off with to say algorithms. Let's see. See over here. Yeah, And let's go over over here in front, if we may come on up. And what are your names? Lazzari. Lazzari. Okay, David. Nice to meet you. Come on up. Sorry. And over here, what's your name? Eric. Okay, David, come on up. Ryan as well. Nice to meet you. Eric. Eric. No. Sorry. Sorry. Eric. Come on over here. Okay, so you came on the stage first. Would you like to go first or go second? You're gonna go second. So, Eric, your first. Come on over here, if you would. So, Eric, behind these seven doors, we have placed in advance the number 50. And we would simply like you the computer to search this array for the number 50 40. I cannot answer that question at this time. Go. Oh, and so that the audience knows what's going on. If you wouldn't mind taking the numbers out to sea. Excellent. Not 50. Now, at this point, yes. You may do whatever you want. Now just find us 50 two. Very good one. Nice. Very good. Nice it was? No. None of them are close to 54 and amazing. Very well done. Very well done. Now, if I may, Eric, what was the algorithm? Via which you found us? The number 50. Linear search. Okay, linear search. Meaning what? To you, Uh, you just go in a line from there until they're okay. That was a very sophisticated answer to return We've not yet introduced. And that's great. Linear surge from left to right. So literally following a line. And was your algorithm correct? Would you say yes? Okay, so it was correct. But there's these different parameters that we want to optimize solutions for not just correctness, but what other property as well. Some even designed right. The efficiency. So was that the most efficient you could have done? Actually, Yeah, I think so. And why do you say that? Because so the numbers are assorted. So at the end of the day, I have to look through. Every single one was just by chance that the 50 was the last. Exactly. So it's it's unfortunate that they were all random. And I didn't want to tell you because I don't want to bias your algorithm, one way or the other. But not knowing if they're sorted and them not even being sorted means that, you know, Betts is the best you could do. Look at all of the doors to find the number and question. And maybe you could have gotten lucky if we had put 50 here. But in the worst case, Eric was, of course, gonna have to do exactly that, searching all of the boxes. So thank you for Eric. Stay on stage with us, if you would for a moment and a round of applause, if we could for finding 50. Theo, we need you not to look at the numbers because Brian needs to do a little bit of magic and he's gonna put some of the numbers back into the locker so literally everyone in the room will know what's going on except you at the moment. But we're going to give you the added bonus this time off, sorting the numbers in advance. So Brian is in the process of sorting some numbers for us. The goal at hand in just a moment is still going to be the find the number 50. I'm really just stalling right now because he's still doing this. I don't really have anything interesting to say just yet. Brian's back. Now, hold on. Would you like to introduce yourself? Maybe. I'm sorry. Sorry for Yuria. I'm a high school student. Senior. Wonderful. Ed. What? School? Team Ridgelines just down the road. Right. We're so glad you could join us here today. And perfect timing, if I may. Now we have seven lockers here behind you. And the goal now is to still find the number 50. But I'm gonna tell you that the numbers are sorted. So what's gonna be your algorithm, if not the same as Eric? And here you go, a minister in the middle. All right, go ahead and show us what's in the middle. Middle number is seven. All right. And now what's your next step gonna be? So I want to get to 50. So assuming that they're sorted, I'm gonna go this way. Go to the rights. Okay, so we have three lockers remaining on the right hand side. What's your instinct now? I'm gonna start with this look, Okay. This one being in the middle of those three and you find 81 anyone to being way too far. So I'm gonna go with this one, which is now in the middle of the two lockers. Bien and a round of applause and congratulations. Thank you. Thanks to you both.
A2 初級 CS50 2019--閱讀3--算法 (CS50 2019 - Lecture 3 - Algorithms) 2 0 林宜悉 發佈於 2021 年 01 月 14 日 更多分享 分享 收藏 回報 影片單字