// Input is integer for sort by (negative for column) // on first line. Second line is space separated // list for first row (specifying number of columns.) // Third and beyond are the following rows (missing // columns get zeroes; extra columns are ignored.) // No input runs the default cases. // Created for this code golf: // https://codegolf.stackexchange.com/questions/172060 // Programming Puzzles & Code Golf // Block-sorting rows and columns in a 2D array // Given a 2D array of integers, let's sort its rows and columns in blocks. This means that you only have to sort a given row or column, but applying the transformations needed for sorting it to every other row or column in the 2D array. // Rules // Input will be a 2D array of integers and a 1-indexed integer. This integer will represent the row to be sorted if the number is positive, or the column to be sorted if the number is negative (or the other way round you want). Example: Given a 4x3 (rows x columns) array you can sort the second column with a -2 argument or the third row with a 3 argument. This second argument will never be zero and its absolute value will never be greater than the corresponding dimension of the array. // Output will be also a 2D array of integers with the needed transformations applied to sort the given row or column. Alternatively you can just write the array to STDOUT. // The output array will have the specified row or column sorted in ascending order. Just note that when you need to swap two numbers in a row, the whole columns where the numbers lay will be swapped. And when you need to swap two numbers in a column, the whole rows where the numbers lay will be swapped. // In the case in which the same number appears several times in the row/column to be sorted, there will be several solutions possible according to the way you swap the values, just do accordingly with the rest of rows/columns to be swapped. // Examples // Positive indices for rows and negative indices for columns /* [5 8 7 6 [1 3 2 4 1 3 2 4 order by -3 (3rd column) --> 9 6 3 0 9 6 3 0] 5 8 7 6] [5 8 7 6 [9 6 3 0 1 3 2 4 order by -4 (4th column) --> 1 3 2 4 9 6 3 0] 5 8 7 6] [5 8 7 6 [5 7 8 6 1 3 2 4 order by 2 (2nd row) --> 1 2 3 4 9 6 3 0] 9 3 6 0] [5 8 7 6 [6 7 8 5 1 3 2 4 order by 3 (3rd row) --> 4 2 3 1 9 6 3 0] 0 3 6 9] [1 2 [1 2 [3 2 3 2] order by -2 (2nd column) --> 3 2] or 1 2] (both are valid) [7 5 9 7 order by 1 [5 7 7 9 [5 7 7 9 1 3 2 4 (1st row) 3 1 4 2 or 3 4 1 2 9 6 3 0] --> 6 9 0 3] 6 0 9 3] */ // This is code-golf, so may the shortest code for each language win! // Expanded function of the lambda. fun process(matrix: Array>, sort: Int) { // If a column sort, can use the builtin method // to sort the rows giving it the column's data // as the value to process. if (sort < 0) { matrix.sortBy {it[-sort-1]} // Otherwise, it's a row sort so transpose the // matrix, use the built in sort, and update // the original. } else { val array = Array(matrix[0].size) {c-> Array(matrix.size) {matrix[it][c]}} array.sortBy {it[sort-1]} (0..matrix.size-1).map {r->(0..matrix[0].size-1) .map {matrix[r][it] = array[it][r]}} } // if } // process // Display the matrix. fun display(matrix: Array>) { // Find the largest value in the matrix. var max = 0 for (row in matrix) for (value in row) if (value > max) max = value // Figure out how much space the largest value // requires to output. var length = 1 while (max != 0) { length++ max /= 10 } // while // Display the matrix. for (row in matrix) { for (value in row) print("%${length}d".format(value)) println() } // for println() } // display // Get the user's test case or process the defaults. fun main(args: Array) { // Lambda function for challenge. val p = // 192 bytes {m:Array>,s:Int->if(s<0){m.sortBy{it[-s-1]}}else{val a=Array(m[0].size){c->Array(m.size){m[it][c]}} a.sortBy{it[s-1]} (0..m.size-1).map{r->(0..m[0].size-1).map{m[r][it]=a[it][r]}}}} // Try get the test case from the user. try { // Read the matrix sort by request, setup a // list for the matrix input, and read the // various rows. val sort = readLine()!!.toInt() val strings = mutableListOf() do { val line = readLine() if (line != null && line.length > 0) strings.add(line) } while (line != null && line.length > 0) // If there is no matrix, throw an exception. if (strings.size == 0) throw IllegalArgumentException("Bad input!") // Get the first row data so we can figure // out how many columns we have. var values = strings[0].split(" ").map { it.toInt()} val size = values.size // If the sort by request doesn't fit our // matrix, throw an exception. if (sort == 0 || (sort < 0 && -sort > size) || (sort > 0 && sort > strings.size)) throw IllegalArgumentException("Bad input!") // Convert the input into our matrix. Display // the original matrix, sort it, and display // the finished product. val array = Array(strings.size) {row -> values = strings[row].split(" ").map { it.toInt()};Array(size) {column -> if (column < values.size) values[column] else 0}} println("Original:") display(array) p(array, sort) println("Sorted by $sort:") display(array) // On exception, complain and process the various // default test cases. } catch (error: Throwable) { // Complain and allocate our test cases. println("Bad input, using defaults!") val data = arrayOf(arrayOf(arrayOf(5, 8, 7, 6), arrayOf(1, 3, 2, 4), arrayOf(9, 6, 3, 0)), arrayOf(arrayOf(1, 2), arrayOf(3, 2)), arrayOf(arrayOf(7, 5, 9, 7), arrayOf(1, 3, 2, 4), arrayOf(9, 6, 3, 0))) val tests = arrayOf(arrayOf(0, -3), arrayOf(0, -4), arrayOf(0, 2), arrayOf(0, 3), arrayOf(1, -2), arrayOf(2, 1)) // For each test, clone the matrix so it doesn't // get modified. Display the original matrix, // sort it, and display the finished product. for (test in tests) { var array = data[test[0]] array = Array(array.size) {row -> Array( array[0].size) {array[row][it]}} println("Original:") display(array) p(array, test[1]) println("Sorted by ${test[1]}:") display(array) } // for } // try } // main

matrixSort cg