1 00:00:00,830 --> 00:00:06,920 Hi everyone, I hope you have tried to code the brute force solution which we discussed in the previous 2 00:00:06,920 --> 00:00:08,570 video on your own. 3 00:00:08,570 --> 00:00:11,780 Now in this video, let's try to code it out together. 4 00:00:11,780 --> 00:00:18,740 Now first let's create a function and let me call this function find indices some. 5 00:00:19,650 --> 00:00:20,070 All right. 6 00:00:20,070 --> 00:00:22,170 So this is find indices some. 7 00:00:22,170 --> 00:00:28,470 And as mentioned in the question the input to the function is an array and the target value. 8 00:00:31,400 --> 00:00:38,720 Now let's have a for loop so that we can iterate through the array. 9 00:00:38,750 --> 00:00:40,820 So let's use a for loop for that. 10 00:00:40,820 --> 00:00:46,760 For let I equal to zero I less than array dot length. 11 00:00:48,020 --> 00:00:50,930 Minus one because I need two values, right? 12 00:00:50,930 --> 00:00:52,820 So let me just show that over here. 13 00:00:54,190 --> 00:00:56,410 So let's say our sample array. 14 00:00:56,410 --> 00:01:01,270 Let me have a sample array over here which is like 12345. 15 00:01:01,270 --> 00:01:04,630 Now let's say we are trying to find the target value. 16 00:01:04,630 --> 00:01:05,860 Let let it be six. 17 00:01:05,860 --> 00:01:07,690 So we are trying to find two values right. 18 00:01:07,690 --> 00:01:15,010 So the I which is the first for loop over here needs only to go up to the previous element, up to the 19 00:01:15,010 --> 00:01:17,350 element previous to the last element in the array. 20 00:01:17,350 --> 00:01:17,650 Right. 21 00:01:17,650 --> 00:01:20,920 Because I will be searching matches for a particular. 22 00:01:20,920 --> 00:01:27,820 I value the value in the array at an ith index with something that is coming after it, right? 23 00:01:27,820 --> 00:01:32,620 So I just need to check I up to I less than array dot length minus one. 24 00:01:32,680 --> 00:01:33,130 All right. 25 00:01:33,160 --> 00:01:35,500 Now let's increment I now. 26 00:01:36,090 --> 00:01:37,260 I plus plus. 27 00:01:37,740 --> 00:01:43,320 Now inside this let's have a for loop again because this is the brute force solution right. 28 00:01:43,320 --> 00:01:47,670 So let's have j let j equal to I plus one. 29 00:01:47,670 --> 00:01:50,010 So I won't be checking for every element right. 30 00:01:50,010 --> 00:01:56,100 If I is equal to one I will check for j values for all the other values which are coming after I. 31 00:01:56,100 --> 00:02:02,670 So when I is equal to one, let me show that over here, if n I is equal to one, I will try j values 32 00:02:02,670 --> 00:02:05,340 two, three, four and five. 33 00:02:05,340 --> 00:02:14,370 Now in the next iteration, when I is equal to two, I will try for j values 345, right? 34 00:02:14,370 --> 00:02:18,150 So I won't check values which are coming before two, right. 35 00:02:18,150 --> 00:02:20,580 Because the value before two is one. 36 00:02:20,580 --> 00:02:26,700 And I, in whatever combination is possible with one, is already checked in the first iteration over 37 00:02:26,700 --> 00:02:27,000 here. 38 00:02:27,000 --> 00:02:28,650 So I don't need to check that over here. 39 00:02:28,650 --> 00:02:28,950 Right. 40 00:02:28,950 --> 00:02:33,720 So that's why we are initializing I as J as I plus one over here. 41 00:02:33,720 --> 00:02:38,730 And this will go on till j less than array dot length. 42 00:02:38,730 --> 00:02:41,700 Now in the previous case we had array dot length minus one. 43 00:02:41,700 --> 00:02:46,710 Because as we saw we will go for I values only up to four over here. 44 00:02:46,710 --> 00:02:49,620 So I can take one I can take the value two. 45 00:02:49,620 --> 00:02:54,540 I can take the value three in the next iteration and four in the next iteration. 46 00:02:54,540 --> 00:02:55,620 And we'll stop over there. 47 00:02:55,620 --> 00:02:58,530 But when it comes to J we will go till the end. 48 00:02:58,530 --> 00:03:00,720 So j less than array dot length. 49 00:03:00,720 --> 00:03:03,270 And let's increment j j plus plus. 50 00:03:03,780 --> 00:03:11,580 Now inside this we are going to check if the value at the ith and jth index of the given array will 51 00:03:11,580 --> 00:03:12,960 add up to the target value. 52 00:03:12,960 --> 00:03:14,220 So that's what we are going to check. 53 00:03:14,220 --> 00:03:16,290 So if target value. 54 00:03:17,630 --> 00:03:18,110 Equal to. 55 00:03:18,110 --> 00:03:18,530 Equal to. 56 00:03:18,530 --> 00:03:19,430 Equal to. 57 00:03:19,580 --> 00:03:22,610 Array at the ith index. 58 00:03:22,610 --> 00:03:26,120 So value at the ith index plus array j. 59 00:03:26,120 --> 00:03:28,790 So the value of the given array at the jth index. 60 00:03:28,790 --> 00:03:31,670 Now if this is true then we have found the answer. 61 00:03:31,670 --> 00:03:35,240 So we just need to return I and j. 62 00:03:35,240 --> 00:03:38,030 So let's return it as an array. 63 00:03:39,530 --> 00:03:44,840 Now, if this is not true, then as per the question, we just need to return an empty array. 64 00:03:44,840 --> 00:03:46,670 And that would happen over here. 65 00:03:46,670 --> 00:03:46,940 Right. 66 00:03:46,940 --> 00:03:48,980 So this is outside the for loop. 67 00:03:48,980 --> 00:03:52,880 So this is outside the uh initial the first for loop. 68 00:03:52,880 --> 00:03:58,520 So when we are coming out of it and if we have not yet returned anything till this point, it means 69 00:03:58,520 --> 00:04:04,040 that we were not able to find a combination of two elements in the array, which adds up to the target 70 00:04:04,040 --> 00:04:04,460 value. 71 00:04:04,460 --> 00:04:05,360 And we are done. 72 00:04:05,360 --> 00:04:09,350 Now let's write a test case to check whether this algorithm is working. 73 00:04:09,350 --> 00:04:11,600 So let's take an example. 74 00:04:11,600 --> 00:04:15,680 Let's say array is equal to 12345. 75 00:04:15,680 --> 00:04:21,980 And let's say the target value is equal to let's say six. 76 00:04:21,980 --> 00:04:22,490 All right. 77 00:04:22,490 --> 00:04:25,130 So one plus five should give us six. 78 00:04:25,130 --> 00:04:30,590 Now let's console log what we get when we call the function console dot log. 79 00:04:31,070 --> 00:04:35,150 Find indices sum and we'll pass the array. 80 00:04:36,350 --> 00:04:38,090 And the target value. 81 00:04:41,080 --> 00:04:43,930 And let's see what we are going to get. 82 00:04:46,550 --> 00:04:48,290 Now I'm going to run this. 83 00:04:49,270 --> 00:04:52,840 And you can see that we are getting two zero comma four, right. 84 00:04:53,050 --> 00:04:54,100 This is zero. 85 00:04:54,520 --> 00:04:57,130 So that's the first element that which is one. 86 00:04:57,130 --> 00:05:02,890 And then the element at the fourth index that's 01234 which is five. 87 00:05:02,890 --> 00:05:04,510 So one plus five is equal to six. 88 00:05:04,510 --> 00:05:07,540 So yes, our, uh code is working. 89 00:05:07,540 --> 00:05:09,520 Now let's try a few more cases. 90 00:05:09,520 --> 00:05:13,240 What will happen if the input array is empty? 91 00:05:13,240 --> 00:05:14,590 Let's try that. 92 00:05:14,590 --> 00:05:17,860 So when that's happening, we are getting an empty array as the output. 93 00:05:17,860 --> 00:05:19,630 So that's correct as per the question. 94 00:05:19,630 --> 00:05:23,410 Now let's say we have uh three values. 95 00:05:23,410 --> 00:05:27,760 But the no combination adds up to the given target value. 96 00:05:27,760 --> 00:05:30,100 So what happens again we are getting an empty array. 97 00:05:30,190 --> 00:05:34,090 And what happens if I have only one element in the given array. 98 00:05:34,090 --> 00:05:35,800 And the target value is also ten. 99 00:05:35,800 --> 00:05:40,780 Now in this case also we are getting an empty array because we need two values that add up to ten as 100 00:05:40,780 --> 00:05:41,680 per the given question. 101 00:05:41,680 --> 00:05:43,840 So yes, our code is working. 102 00:05:43,840 --> 00:05:48,370 Now let's take a relook at the code and see what's happening over here.