Is there any efficient way to sort a 2 dimensional array in java like using Arrays.sort()
.For ex:-
a={{3 ,1},{0,2})
result={{0,1},{2,3}}
This was my approach:
for (int x = 0; x < n; x++) {
for (int y = 0; y < n; y++) {
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (grid[i][j] > grid[x][y]) {
int t = grid[x][y];
grid[x][y] = grid[i][j];
grid[i][j] = t;
}
}
}
}
}
You can solve your problem using :
public static void main(String[] args) {
Integer[][] a = {{3, 1}, {0, 2}};
List<Integer> list = new ArrayList<>();
for (Integer[] i : a) {//<--convert the 2d to list-------------------------(1)
list.addAll(Arrays.asList(i));
}
Collections.sort(list);//<--sort this list---------------------------------(2)
Integer[][] result = new Integer[a.length][];//create new 2d array---------(3)
int k = 0;
for (int i = 0; i < a.length; i++) {//loop throw the original array--------(4)
//creae temp array with the same size of each 1d array-----------------(5)
Integer[] temp = new Integer[a[i].length];
//loop and fill temp array with elements of the list-------------------(6)
for (int j = 0; j < a[i].length; j++) {
temp[j] = list.get(k);
k++;
}
result[i] = temp;//add the temp to the new array-----------------------(7)
}
System.out.println(Arrays.deepToString(result));//print the new array
}
example
input output
{{3, 1}, {0, 2}} [[0, 1], [2, 3]]
{{3, 1, 5}, {0, 2}} [[0, 1, 2], [3, 5]]
{{3, 1, 5}, {0, 5}, {3, 7, 5}, {10, 9, 11}} [[0, 1, 3], [3, 5], [5, 5, 7], [9, 10, 11]]
Note this solution will assure the same length of each node of the original array.
You can sort all the elements first and then generate pair or n
elements, eg;
int[][] a={{3 ,1},{0,2}};
int count = a[0].length;
//Sort the elements
List<Integer> sortedElements = Arrays.stream(a)
.flatMapToInt(e -> Arrays.stream(e))
.boxed()
.sorted()
.collect(Collectors.toList());
//Now, generate 2D arrays
int[][] arrays = new int[a.length][];
int[] temp = new int[count];
int index = 0;
for(int i = 0; i < sortedElements.size() ; i++){
if(i % count == 0 && i != 0){
arrays[index++] = temp;
temp = new int[count];
}
temp[i % count] = sortedElements.get(i);
}
arrays[index++] = temp;
for(int[] e : arrays){
System.out.println(Arrays.toString(e));
}
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