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why we are doing modulo for all element of the array and not only the last element?

This talk is the best, because you spend most of the time on the math. For so many of us, coding is easy and combinatorics is hard, yet this is the only talk I found that explains the math. Thank you so much.

Thank you This was good explanation

thanks I finally understand

f[0] is 1 which means there is only one way to build fp[0]: "no block". Thus you can just manually caculate f[0]~f[3] and f[4]=f[0]+f[1]+f[2]+f[3]=8

helper直接//2就好了 谢谢 代码很清楚

Great explanation, helped me understand this difficult problem. Thanks for the effort you put into this video.

Finally someone who describes the algorithm behind the solution. This is very well done.

python3 class Solution: def visibleMountains(self, peaks: List[List[int]]) -> int: # sort peaks in ascending order of (x - y) x-intercept # and also in descending order of (x + y) x-intercept peaks.sort(key=lambda x: ((x[0] - x[1]), -(x[0] + x[1]))) count = 0 max_end = float('-inf') for i, (x, y) in enumerate(peaks): if x + y > max_end: max_end = x + y if i < len(peaks) - 1 and peaks[i] == peaks[i + 1]: continue count += 1 return count

感谢分享，很清晰易懂的解释！

Lulu did you come up with this solution independently? Such a genius

Hey Lulu, thanks for the explain. I didnt get why we are recursing the *width - the width* of each blocks in minute 7:36

In the first step when calculating the number of ways you can build a single wall layer of length 6, why do we add the four previous ones? I don't understnad that part

Awesome solution and eloborated explanation, thanks for clarifying this problem!

Thank you very much, I was stucked

many thanks for your video

Thank you so much for this explanation. It really helped.

Very gorgeous and lucid! Thanks for saving time!

Awesome explanation Lulu!

im confused about this "counter" variable. at 6:48 the median is 4 not 3.

Thank you. May you be blessed. I wanted logical help and it was the best resource. Rest of the internet had code.

好欢乐，还有bgm

good

Great explanation: well-structured, concise, with a practical walkthrough. Many thanks!

omg you actually taught me😂, thanks a lot

great explanation. Thanks a lot. This is a harder question.

Nice

nice coding keep it up ,)

To those who are wondering: We counted (1, 3) combo as 4 but (3, 1) as 1 cuz if we break 3 in (3, 1) it will break into (1, 2, 1) and (2, 1, 1) which can already be covered by previous considerations from (2, 2) and (1, 3) so to avoid overlapping it has been done so.

You did a great job explaining the intuition on this one thank you!

Great explanation! thank you so much!!

Brute force solution : #assume the widest base and tallest mountain max_x = input[0][0] max_y = input[0][1] #calculate the widest base and tallest mountain for i in input: left_base = i[0]-i[1] right_base = i[0]+i[1] max_x = max(max_x, left_base) max_y = max(max_y, i[1]) #generate a 2D map of the scenery scenery = [[0 for i in range(max_y+1)] for j in range(-1*max_x, max_x + 1)] #populate the overlapping mountains for i in input: scenery[i[0]][i[1]] += 1 temp_y = i[1] - 1 counter = 1 while (temp_y > 0): for j in range(counter): scenery[i[0]-j][temp_y] += 1 scenery[i[0]+j][temp_y] += 1 counter += 1 temp_y -= 1 #Find the peaks which are not overlapped visible_mountain = 0 for i in input: if scenery[i[0]][i[1]] == 1: visible_mountain += 1 print(visible_mountain)

Thanks for the solution, Lulu! Could you please explain why is the total of ways to have a split in the wall is a multiplication of number of ways to build left-i and right-i?

Hi, Lulu. Greetings from Lulu.

The explanation was quite good, but it could have been even better with the code

I am trying to solve this problem right now. Your video came in the right moment. Thank you so much.

well explained thanks

28:11 total = 0,1,8,32(should be 64)

Thanks for your nice explanation! <3

Great Explanation, Thanks Keep it Up

Explanation was good but it would be more helpful if you explain the code too, Btw keep up the good work. 🙌🙌

if this is ur original voice then let me say your voice is very cute

Thanks