1 00:00:00,550 --> 00:00:01,510 Hi everyone. 2 00:00:01,510 --> 00:00:04,330 In this video let's talk about two questions. 3 00:00:04,330 --> 00:00:06,940 The first question is what are data structures? 4 00:00:06,940 --> 00:00:11,890 And the second question is why do you need to learn them to ace coding interviews. 5 00:00:11,890 --> 00:00:12,370 All right. 6 00:00:12,370 --> 00:00:14,290 So let's get started with the first question. 7 00:00:14,290 --> 00:00:21,160 What are data structures now as per Wikipedia, data structures are just a collection of data values 8 00:00:21,610 --> 00:00:24,100 and relationships among them. 9 00:00:24,490 --> 00:00:29,290 And the functions or operations that can be applied to the data. 10 00:00:29,290 --> 00:00:32,350 So this is what Wikipedia defines data structures to be. 11 00:00:32,350 --> 00:00:38,380 Now let's take these three components of the definition and try to understand what data structures are. 12 00:00:38,410 --> 00:00:42,400 For this let's take a very familiar data structure which is arrays. 13 00:00:42,400 --> 00:00:44,980 So let's say this is an array which we have. 14 00:00:44,980 --> 00:00:47,140 So you can see it has four values in it. 15 00:00:47,140 --> 00:00:53,170 Now over here if you look at this array over here you can agree that this is a collection of data values. 16 00:00:53,170 --> 00:00:55,780 So we have a check mark to the first condition over here. 17 00:00:55,780 --> 00:00:58,960 So the data values over here are 156 and eight. 18 00:00:58,990 --> 00:01:03,040 Now we can also see that there are relationships among these data values. 19 00:01:03,040 --> 00:01:03,940 Now what is it. 20 00:01:03,940 --> 00:01:09,400 For example in the case of arrays we have the indices over here zero, one two and three. 21 00:01:09,400 --> 00:01:12,610 So yes there is a relationship between these two values right. 22 00:01:12,610 --> 00:01:15,040 For example this is the value before. 23 00:01:15,040 --> 00:01:19,240 This value over here is before this because this is index zero and this is index one. 24 00:01:19,240 --> 00:01:21,970 So there is a relationship among these data values. 25 00:01:21,970 --> 00:01:26,530 And then finally there are functions or operations that can be applied to them. 26 00:01:26,530 --> 00:01:26,980 Right. 27 00:01:26,980 --> 00:01:29,860 Or let's say we have we call this array over here. 28 00:01:29,860 --> 00:01:30,280 Ah. 29 00:01:30,280 --> 00:01:33,670 So we let's say we say const r is equal to 1568. 30 00:01:33,670 --> 00:01:35,740 So the array over here is called r. 31 00:01:35,770 --> 00:01:41,350 Now if we want to push another value to the array we can say r dot push and then give the value right. 32 00:01:41,350 --> 00:01:44,440 So this is actually a function which is inbuilt. 33 00:01:44,440 --> 00:01:47,860 And this can do operations on the array which is given to us. 34 00:01:47,860 --> 00:01:51,310 So that's why we can say an array is a data structure. 35 00:01:51,310 --> 00:01:56,740 And in fact an array is a pre-built data structure which is there in almost every programming language. 36 00:01:56,740 --> 00:01:59,770 And definitely it is there pre-built in JavaScript. 37 00:01:59,770 --> 00:02:06,670 Now we will also be coding and building some of some other data structures from scratch as we go ahead 38 00:02:06,670 --> 00:02:07,600 with this course. 39 00:02:07,600 --> 00:02:12,700 So we are done and we have understood the first question, which is what are data structures? 40 00:02:12,700 --> 00:02:18,850 Now let's go to the second question, which is why do you need to learn data structures to be able to 41 00:02:18,850 --> 00:02:20,350 ace coding interviews? 42 00:02:20,350 --> 00:02:27,490 So in coding interviews we will be given some input and we will be asked to write an algorithm that 43 00:02:27,490 --> 00:02:31,990 can manipulate the input which is given to us to arrive at the desired output. 44 00:02:31,990 --> 00:02:35,740 So this is basically what coding interviews is all about right now. 45 00:02:35,740 --> 00:02:38,950 The input and the output is actually just data. 46 00:02:38,950 --> 00:02:40,990 So you would be given some data. 47 00:02:40,990 --> 00:02:43,480 You write an algorithm to get the result right. 48 00:02:43,480 --> 00:02:48,880 For example, let's say you're given two numbers A and B and the algorithm is to add these two numbers 49 00:02:48,880 --> 00:02:49,690 a plus b. 50 00:02:49,690 --> 00:02:54,280 And the output that you're getting is the sum, which is let's say sum is equal to a plus b. 51 00:02:54,280 --> 00:02:56,590 So the output is the sum which is s right. 52 00:02:56,590 --> 00:02:58,930 So this is actually a very simple algorithm. 53 00:02:58,930 --> 00:03:02,440 And again every coding interview question follows this pattern. 54 00:03:02,440 --> 00:03:08,110 Now when you take a look at questions in which come up in the coding interviews, you can solve these 55 00:03:08,110 --> 00:03:10,030 questions in multiple ways. 56 00:03:10,030 --> 00:03:14,980 So that means you can write different algorithms and you can get the required output. 57 00:03:14,980 --> 00:03:21,040 But then there are some data structures that are more efficient than others to do some tasks. 58 00:03:21,040 --> 00:03:26,320 So what do we mean with more efficient now because we are dealing with computers, efficiency over here 59 00:03:26,320 --> 00:03:32,410 means it may take some algorithms, may take less time to solve the question, or some algorithms may 60 00:03:32,410 --> 00:03:34,810 take less space to solve the question. 61 00:03:34,810 --> 00:03:35,200 All right. 62 00:03:35,200 --> 00:03:42,430 So that's why it's very important to have a hands on understanding with all the common data structures 63 00:03:42,430 --> 00:03:47,680 to be able to solve coding interview questions in the best or in an efficient manner. 64 00:03:47,680 --> 00:03:50,920 So you have to be hands on with the common data structures. 65 00:03:50,920 --> 00:03:56,290 You have to know their positives and negatives of different data structures, and what data structure 66 00:03:56,290 --> 00:03:59,590 is suitable for different types of scenarios or tasks. 67 00:03:59,590 --> 00:04:06,160 Now, the good news is that the number of common data structures is pretty well defined, and you can 68 00:04:06,160 --> 00:04:11,050 easily get hands on and good with these data structures in a short period of time. 69 00:04:11,050 --> 00:04:12,280 So let's go ahead. 70 00:04:12,280 --> 00:04:17,740 And in this course, as we see as we get introduced to new data structures, we will try to learn the 71 00:04:17,740 --> 00:04:18,760 theory behind them. 72 00:04:18,760 --> 00:04:22,240 We will have crash courses on those specific data structures. 73 00:04:22,240 --> 00:04:28,300 We will try to analyze the Big-O complexity with respect to time and space for various actions or operations. 74 00:04:28,300 --> 00:04:33,850 And we will learn as we keep going on with the course, what data structure to use for what type of 75 00:04:33,850 --> 00:04:34,390 questions.