Thread: 2Darray in 1Darray and sum elements

Yes, so my solution describes how to get to a certain element in that array.

You will have to write the code to figure out what column sums are and such.

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Mats

Originally Posted by matsp

Yes, so my solution describes how to get to a certain element in that array.

You will have to write the code to figure out what column sums are and such.

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Mats

No i don't think so or i didn't understand.If we have array[i][j] we say

PHP Code:

for i=0; i<n
   for j=0 j<n 


So in 1D array[t] i have only t for loop and thought that must do these(hope are correct)

for the sum of the the rows in array[t] we must make 3 loops and for each loop i must calcuate the sum each t/n=3 elements (from 0-2, 3-5, 6-8 )
for the rows i must sum example the array[0] + array[t/n] + array[2t/n]

So, if we take a 9-element array and "make it into a 2D array", it would have the following indices:

Code:

[0] = [0][0]   [1] = [0][1]   [2]=[0][2]
[3] = [1][0]   [4] = [1][1]   [5]=[1][2]
[6] = [2][0]   [7] = [2][1]   [8]=[2][2]

So to get to element [y][x], we use [y *n + x] - for example, x = 1, y = 1 -> 1*3 + 1 -> 4; x = 0, y = 2 -> 2*3 + 0 -> 6.

Does this make sense to you?

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Mats

Yes thank you very much.Now i understand what you mean.