CODEWITHSUNDEEP
javaalgorithmarraylist
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Reputation: 157

"Rotating" a ArrayList<Integer>

I have an ArrayList in the board game-like game I am developing in Java, I format this ArrayList as a square, as so (numbers being indexs);

/*
 *  |0 |1 |2 |3 |
 *  |4 |5 |6 |7 |
 *  |8 |9 |10|11|
 *  |12|13|14|15|
 */

What I want to do is take this ArrayList and rotate it;

e.g turn() would output (based on the original index)

/*
 *  |0 |4 |8 |12|
 *  |1 |5 |9 |13|
 *  |2 |6 |10|14|
 *  |3 |7 |11|15|
 */

My current approach is breaking the ArrayList in to rows with a getRow() function i wrote and manually writing the rows back

Upvotes: 0

Views: 644

Answers (1)

user1935024
user1935024

Reputation: 

for(int i = 0; i < 4; ++i){
        for(int j = i; j < 4; ++j){
            int t1 = al.get(i).get(j);
            al.get(i).set(j, al.get(j).get(i));
            al.get(j).set(i, t1);
        }
    }

it's called matrix transpose.

Upvotes: 1

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