We are given a 2D array of order N X M and a column number K ( 1<=K<=m). Our task is to sort the 2D array according to values in the Column K.

Examples:

Input : If our 2D array is given as (Order 4X4) 39 271142 10 939190 54 785689 24 642065 Sorting it by values in column 3 Output : 39 271142 24 642065 54 785689 10 939190

**The Idea is to use** **Arrays.sort in Java**.

`// Java Code to sort 2D Matrix` `// according to any Column` `import` `java.util.*;` `class` `sort2DMatrixbycolumn {` ` ` ` ` `// Function to sort by column` ` ` `public` `static` `void` `sortbyColumn(` `int` `arr[][], ` `int` `col)` ` ` `{` ` ` `// Using built-in sort function Arrays.sort` ` ` `Arrays.sort(arr, ` `new` `Comparator<` `int` `[]>() {` ` ` ` ` `@Override` ` ` `// Compare values according to columns` ` ` `public` `int` `compare(` `final` `int` `[] entry1, ` ` ` `final` `int` `[] entry2) {` ` ` ` ` `// To sort in descending order revert ` ` ` `// the '>' Operator` ` ` `if` `(entry1[col] > entry2[col])` ` ` `return` `1` `;` ` ` `else` ` ` `return` `-` `1` `;` ` ` `}` ` ` `}); ` `// End of function call sort().` ` ` `}` ` ` ` ` `// Driver Code` ` ` `public` `static` `void` `main(String args[])` ` ` `{` ` ` `int` `matrix[][] = { { ` `39` `, ` `27` `, ` `11` `, ` `42` `},` ` ` `{ ` `10` `, ` `93` `, ` `91` `, ` `90` `},` ` ` `{ ` `54` `, ` `78` `, ` `56` `, ` `89` `},` ` ` `{ ` `24` `, ` `64` `, ` `20` `, ` `65` `} };` ` ` `// Sort this matrix by 3rd Column` ` ` `int` `col = ` `3` `;` ` ` `sortbyColumn(matrix, col - ` `1` `);` ` ` ` ` `// Display the sorted Matrix` ` ` `for` `(` `int` `i = ` `0` `; i < matrix.length; i++) {` ` ` `for` `(` `int` `j = ` `0` `; j < matrix[i].length; j++)` ` ` `System.out.print(matrix[i][j] + ` `" "` `);` ` ` `System.out.println();` ` ` `}` ` ` `}` `}` |

Output:

39 27 11 42 24 64 20 65 54 78 56 89 10 93 91 90

**Time complexity **: O(n Log n) where n is number of rows. Here assumption is that the sort() function uses a O(n Log n) sorting algorithm.

This article is contributed by **DANISH KALEEM**. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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