I have a square 2d array of values, where each row is identical, and where each element of row is one bigger than the last. For example:
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
I want to filter them, such that I can make a diamond as such:
1
1 2 3
1 2 3 4 5
1 2 3 4 5 6 7
1 2 3 4 5
1 2 3
1
Notice how the first part of the array is used, no matter how many elements are to be printed on that line. Also, spacing doesn't matter. I spaced them to show the diamond.
I know how to filter the top right "chunk" out, using j-i<(j/2). This will convert the original square into:
1
1 2 3
1 2 3 4 5
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
How can I get the bottom right "chunk" to filter out also? What additional condition can I impose on the values?
Presuming you have found out and stored the length of the "side" of the square already then you could use something like below. However, if your square has an even length then it will not work (can't produce a diamond in this way from an even side length square).
The following is pseudo-code so you will need to adapt it for your language. I've also used 0-indexed arrays and presumed square is a 2D array.
for (i=0, i<length, i++)
{
for (j=0, j<Length, j++)
{
if (i < length/2)
{
if (j < length/2 AND j <= i)
print square[i][j]
}
}
else
{
if (j < length/2 AND j <= (length - i))
{
print square[i][j]
}
}
}
print newline
}
Related
How to loop a 2D array, such as
1 2 3 4
5 6 7 8
9 10 11 12
choose one from each line everytime, left first. The expected order for the example is:
1 5 9
2 5 9
1 6 9
1 5 10
2 6 9
2 5 10
1 6 10
2 6 10
....
Thanks.
you can try two for loops
$a[$row][$column];
for($i=0; $i <$row; i++) {
for($j=0; $j<$column;$j++){
echo $a[$j][$i];
}
}
you can indent after 1 loop
I am trying to construct a 2D array for an assignment. I've used a nested for loop to construct the 2D array using scanf():
int width;
int height;
scanf("%d %d",&width,&height);
int array[width][height];
for (int i=0;i<height;i++){
for (int j=0;j<width;j++){
scanf("%d",&array[i][j]);
}
}
However when I print the array, I can see that it has been constructed in a strange way, where all the numbers of the first line past a certain point are the first few numbers from the second line (instead of what they should be). The next lines after work fine.
Example:
Input:
6 2
1 3 5 7 9 1
2 4 6 8 0 2
3 4 2 0 1 3
The created array looks like this:
1 3 2 4 6 8 (<-- these last 4 numbers are the first 4 numbers of the second line)
2 4 6 8 0 2 (correct)
3 4 2 0 1 3 (correct)
Any ideas? Thanks a lot.
Your declaration of array
int array[width][height];
is wrong. The outer loop goes from 0 to height - 1, but array[i] can only go
from 0 to width - 1. The same applies for the inner loop. You swapped width
and height in the declaration of the array, it should be
int array[height][width];
Also note that for the matrix
1 3 5 7 9 1
2 4 6 8 0 2
3 4 2 0 1 3
the width is 6 and the height is 3, so the correct input should be
6 3
1 3 5 7 9 1
2 4 6 8 0 2
3 4 2 0 1 3
I compiled and run this code:
#include <stdio.h>
int main(void)
{
int width;
int height;
scanf("%d %d",&width,&height);
int array[height][width];
for (int i=0;i<height;i++){
for (int j=0;j<width;j++){
scanf("%d",&array[i][j]);
}
}
printf("----------------\n");
for (int i=0;i<height;i++){
for (int j=0;j<width;j++){
printf("%d ", array[i][j]);
}
printf("\n");
}
}
And the output is:
$ ./b
6 3
1 3 5 7 9 1
2 4 6 8 0 2
3 4 2 0 1 3
----------------
1 3 5 7 9 1
2 4 6 8 0 2
3 4 2 0 1 3
as you can see, now it's reading correctly. See https://ideone.com/OJjj0Y
I have the following matrix:
[ 2 5 7 8 1 3 4 6 5 7 3 1;
1 1 1 1 2 2 2 2 3 3 3 3;]
The first row represents values and the second characteristic
I want to get the max value if the value in the second row is the same, i.e. their characteristic is the same. So, what I would like to have is:
[ 8 6 7], since 8 is the highest value when the second row is 1, 6 when the second row is is 2, and 7 when the second row is 3. I can do it with a loop, but I would like vectorized solution, and if possible of course, in one line.
accumarray does exactly what you want
x=[ 2 5 7 8 1 3 4 6 5 7 3 1; 1 1 1 1 2 2 2 2 3 3 3 3;]
accumarray(x(2,:)',x(1,:)',[],#max)
I have got a question regarding all the combinations of matrix-rows in Matlab.
I currently have a matrix with the following structure:
1 2
1 3
1 4
2 3
2 4
3 4
Now I want to get all the possible combinations of these "pairs" without using a number twice in the same row:
1 2 3 4
1 3 2 4
1 4 2 3
And it must be possible to make it with n-"doublecolumns". Which means, when my pair-matrix goes for example until "5 6", i want to create the matrix with 3 of these doublecolumns:
1 2 3 4 5 6
1 2 3 5 4 6
1 2 3 6 4 5
1 3 2 4 5 6
1 3 2 5 4 6
....
I hope you understand what I mean :)
Any ideas how to solve this?
Thanks and best regard
Jonas
M = [1 2
1 3
1 4
2 3
2 4
3 4]; %// example data
n = floor(max(M(:))/2); %// size of tuples. Compute this way, or set manually
p = nchoosek(1:size(M,1), n).'; %'// generate all n-tuples of row indices
R = reshape(M(p,:).', n*size(M,2), []).'; %// generate result...
R = R(all(diff(sort(R.'))),:); %'//...removing combinations with repeated values
i want to have 10 different shuffled form of an array...but random_shuffle produce the same sequence for 10 times...
and my code is...
for(k=0;k<10;k++) {
for (l=0; l<SIZE;l++)
a[l]=l+1;
srand(time(0));
random_shuffle(a,a+SIZE); //getting the shuffled sequence
for(;i<10;i++) {
for(j=0;j<5;j++) {
rcusseq[i][j]=a[m++]; //storing the sequence in a 2d array
printf("%d\t",rcusseq[i][j]);
}
m=0;
printf("\n");
}
}
OUTPUT
5 4 2 1 3
5 4 2 1 3
5 4 2 1 3
5 4 2 1 3
5 4 2 1 3
5 4 2 1 3
5 4 2 1 3
5 4 2 1 3
5 4 2 1 3
5 4 2 1 3
Press any key to continue
You're reinitializing the random number generator each time, as your code is quick enough to run within 1 second, you get the same seed every time.
Move srand(time(0));out of the loop.
Only call srand() once in a program, e.g. at the beginning of main().