1 00:00:00,687 --> 00:00:01,270 PROFESSOR: Hi. 2 00:00:01,270 --> 00:00:05,600 Do you know that Google stores 45 billion web 3 00:00:05,600 --> 00:00:06,910 pages on the internet? 4 00:00:06,910 --> 00:00:09,240 And if every single page was a sheet of paper 5 00:00:09,240 --> 00:00:11,810 and we stacked them up real high, 6 00:00:11,810 --> 00:00:17,970 that would be a tower 610 times taller than Mount Everest? 7 00:00:17,970 --> 00:00:18,470 Whoa. 8 00:00:18,470 --> 00:00:22,290 And if that's not mind blowing enough, 9 00:00:22,290 --> 00:00:25,050 Google is able to give you your search results in a split 10 00:00:25,050 --> 00:00:26,200 second. 11 00:00:26,200 --> 00:00:27,660 So how can Google do that? 12 00:00:27,660 --> 00:00:30,920 I mean, that's like finding a needle in a haystack. 13 00:00:30,920 --> 00:00:34,450 And so what I was thinking of is showing 14 00:00:34,450 --> 00:00:37,190 the analogy of a search algorithm, 15 00:00:37,190 --> 00:00:40,700 like this, through a hotel. 16 00:00:40,700 --> 00:00:43,640 So imagine I have a friend, James, 17 00:00:43,640 --> 00:00:45,435 and I'm looking for James in the hotel 18 00:00:45,435 --> 00:00:48,710 and he's hiding in one of the doors of the hotel rooms. 19 00:00:48,710 --> 00:00:52,210 And assume that the hotel rooms are arranged 20 00:00:52,210 --> 00:00:55,750 in a numerical order and the people in the hotel 21 00:00:55,750 --> 00:00:57,360 are arranged in alphabetical order 22 00:00:57,360 --> 00:00:59,820 to the numbers behind them. 23 00:00:59,820 --> 00:01:04,379 And so the easiest way, I guess, you could think of 24 00:01:04,379 --> 00:01:07,500 to find James is to just run through the doors, 25 00:01:07,500 --> 00:01:10,700 opening every single one, and say, is James here? 26 00:01:10,700 --> 00:01:11,460 Is James here? 27 00:01:11,460 --> 00:01:12,070 Is James here? 28 00:01:12,070 --> 00:01:13,470 And so on. 29 00:01:13,470 --> 00:01:20,100 But the fastest way to do it is to run to the middle door 30 00:01:20,100 --> 00:01:22,030 and to open the door and say, is James here? 31 00:01:22,030 --> 00:01:24,910 And if James isn't there, you ask him, who are you? 32 00:01:24,910 --> 00:01:27,710 Well, this other person says, well, my name is Daniel. 33 00:01:27,710 --> 00:01:29,670 Then you would instantly know, oh, 34 00:01:29,670 --> 00:01:31,580 the people on the left of this door 35 00:01:31,580 --> 00:01:36,000 are people whose names start with A, B, and C. 36 00:01:36,000 --> 00:01:37,870 And the people on the right-hand of the door 37 00:01:37,870 --> 00:01:43,110 will be people from D onwards, D, E, F, H. 38 00:01:43,110 --> 00:01:47,610 And then you realize, oh, so if I'm looking for James, 39 00:01:47,610 --> 00:01:49,240 James is on the right-hand side. 40 00:01:49,240 --> 00:01:53,030 And so you will run to the door right 41 00:01:53,030 --> 00:01:55,250 in the middle of the section you just 42 00:01:55,250 --> 00:01:58,190 cut on the right-hand side, and then you will ask again, 43 00:01:58,190 --> 00:01:58,990 is James here? 44 00:01:58,990 --> 00:02:01,500 If James isn't there, you would try to figure out, 45 00:02:01,500 --> 00:02:03,260 is f on the left-hand side of the grid 46 00:02:03,260 --> 00:02:05,760 or on the right-side of the grid, and so on. 47 00:02:05,760 --> 00:02:08,539 And that way you get to your results 48 00:02:08,539 --> 00:02:15,030 real fast instead of just trying it one at a time. 49 00:02:15,030 --> 00:02:17,340 Now, I guess what I wanted to get out 50 00:02:17,340 --> 00:02:18,910 of this video to the people out there 51 00:02:18,910 --> 00:02:21,890 is to blow their minds on the simplicity of some 52 00:02:21,890 --> 00:02:25,010 of these algorithms and to say, whoa, 53 00:02:25,010 --> 00:02:29,640 if I can understand that-- and to say that just knowing 54 00:02:29,640 --> 00:02:31,530 that something is a little bit better 55 00:02:31,530 --> 00:02:36,510 actually makes a humongous difference in the real world. 56 00:02:36,510 --> 00:02:39,940 And that's what I want to get out of the video.