Pascal's Triangle II - Leetcode 119 - Python

[@m.kamalali]

We can do the follow up using only 1 array by updating the array backward row=[1] for i in range(rowIndex): row.append(1) for j in range(i,0,-1): row[j]+=row[j-1] return row

[@commonguy7]

fkin genious bro

[@VidyaBhandary]

A Q&A video and two problems .. you are on a roll. Thanks for making these videos !

[@YehorKozyr]

This solution works, but it doesn't cover the mathematical meaning of Pascal's triangle and therefore can be simplified into a time and space O(rowIndex) function with a calculation of binomial coefficients.

[@pbenikovszky1]

sure, and the cpu will easily handle rowindex 1000 :D

[@sickboydroid]

@@pbenikovszky1 there is a easier way to calculate binomial coefficients without calculating factorials. Here is js version: function nCr(n, r) { if(r === 0 || n === r) return 1; if(r > n/2) r = n-r; let res = 1; for(let i = 1; i

[@rajanmaheshwari]

Just did this few hours back 😃

[@xaceffulgent]

Discovered this channel recently and am learning a lot! Thank you! Beginner question: why do you put your sol in a class?

[@chuckle_pugz96]

'cause leetcode is passing all the inputs to this class in the background. Though some sites just use a function.

[@krateskim4169]

Awesome solution

[@ashesh8085]

My approach to this problem was to try to figure out a function such that: f(n, i) = ans[i] ; Meaning there would be a function which when given the rowIndex would be able to calculate the value of i th element in the row. Does a function like this exist? Is it even possible? This to me would seem much more efficient. Here are some examples of this functions: f(5,5) = 1 f(4,2) = 6 f(5,2) = 10 f(5,3) = 10 f(n, 0) = 1 f(n, n) = 1 .... etc. Update: This is the binomial coefficient function

[@Mercer80]

C++ class Solution { public: vector getRow(int rowIndex) { vectorprev(rowIndex+1); for(int r=0;r

[@bud2725]

hi @NeetCodeIO code isn't working for current format of the question Leetcode 119. Code returns [1] always. Can you please check? Thank you

[@AustinWeeks]

my friend you have to figure it out on your own sometimes

[@waqasbutt61]

you need to reassign res = next_row after the end of the inner for loop

[@reqzonegaming7157]

Please Bro Make video for 2905. Find Indices With Index and Value Difference II

[@MrBomb72]

There’s a good quality one here: kzbin.info/www/bejne/f32UgXVun9OZnqcfeature=shared (found this from the top rated post under the solutions tab)

[@infoknow3278]

Easiest to come up with class Solution: def getRow(self, rowIndex: int) -> List[int]: res = [[1]] for i in range(rowIndex): tmp = [0] + res[-1] + [0] row = [] for j in range(len(res[-1])+1): row.append(tmp[j]+tmp[j+1]) res.append(row) return res[rowIndex]

[@sickboydroid]

for math nerds: ---------------------------------------------------------------- TC: O(rowIndex) SC: O(rowIndex) ---------------------------------------------------------------- var getRow = function(rowIndex) { if(rowIndex === 0) return [1]; const row = new Array(rowIndex+1); for(let i = 0; i n/2) r = n-r; let res = 1; for(let i = 1; i