// Input: nothing for the default test cases // or n lines of n space separated integers // for the matrix, plus a line of n space // separated integers that are unique between // zero and one less than n. // Created for this code golf challenge: // https://codegolf.stackexchange.com/q/193254 // Reorder a matrix, twice // You are given a square n×n // matrix A, and a list (or vector) u of // length n containing the numbers 1 through // n (or 0 through n−1). Your task is to // reorder the columns and rows of the // matrix A according to the order specified // in u. // That is, you will construct a matrix B // where the (i,j)-th element is the (u(i), // u(j))-th element of A. You should also // output the inverse of this action; that // is, the (i,j)-th element of A will end // up at position (u(i),u(j)) in a new // matrix C. // For example, given // A = [ // 11 21 31 // 12 22 32 // 13 23 33], // u = [3 1 2] // 2 0 1 // 1 2 0 // the output should be // B = [ // 33 13 23 // 31 11 21 // 32 12 22], // C = [ // 22 32 12 // 23 33 13 // 21 31 11] // You may take input and output through any // of the default I/O methods. You do not have // to specify which matrix is B or C, as long // as you output both. You may assume A only // contains positive integers. You must support // matrices up to at least size 64×64. // Example // ===== Input ===== // A = [ // 35 1 6 26 19 24 // 3 32 7 21 23 25 // 31 9 2 22 27 20 // 8 28 33 17 10 15 // 30 5 34 12 14 16 // 4 36 29 13 18 11] // u = [3 5 6 1 4 2] // ==== Output ===== // B = [ // 2 27 20 31 22 9 // 34 14 16 30 12 5 // 29 18 11 4 13 36 // 6 19 24 35 26 1 // 33 10 15 8 17 28 // 7 23 25 3 21 32] // C = [ // 17 15 8 10 28 33 // 13 11 4 18 36 29 // 26 24 35 19 1 6 // 12 16 30 14 5 34 // 21 25 3 23 32 7 // 22 20 31 27 9 2] // Expanded function of the lambda with // comments. fun switch(a: List>, u: List) { // Get the size of our matrix and index // substitution list. Generate our B matrix // using the list to find our A matrix // values. For each line in the resulting // matrix, combine the elements into a // string and display it. val size = u.size for (line in List(size) { row -> List(size) { column -> a[u[row]][u[column]] } }) println(line.joinToString(" ")) // Generate our C matrix using the index // within list to find our A matrix values. // For each line in the resulting matrix, // combine the elements into a string and // display it. for (line in List(size) { row -> List(size) { column -> a[u.indexOf(row)][ u.indexOf(column)] } }) println(line.joinToString(" ")) } // switch // Function to display our inputs prior to // using the lambda to process them. fun process(a: List>, u: List) { // Lambda to perform the challenge. See the // expanded version for comments. val s = // 213 bytes {a:List>,u:List->val s=u.size for(l in List(s){r->List(s){c->a[u[r]][u[c]]}})println(l.joinToString(" ")) for(l in List(s){r->List(s){c->a[u.indexOf(r)][u.indexOf(c)]}})println(l.joinToString(" "))} // For each line in the original matrix, // combine the elements into a string and // display it. Combine the elements of our // index substitution into a string and // display it. Call the lambda to display // our results. for (line in a) println(line.joinToString(" ")) println("\n${u.joinToString(" ")}\n") s(a, u) println() } // process // Main function for this challenge. fun main(args: Array) { // Try reading our matrix and index // substitution list from the user. try { // Default our matrix to empty and our // size to one, While we haven't gotten // all of the lines in the matrix, read // the next one. val matrix = MutableList(0) { listOf(0) } var size = 1 while (matrix.size < size) { // Read the line, split it by spaces, // and convert the string to an integer. // Cause an exception on end of file // or non integer data. val data = readLine()!!.split(" ").map { it.toInt() } // If this is our first line, our size // to look for in the future is the // number of integers we just read, if (matrix.size == 0) size = data.size // Otherwise, if this line doesn't // have the number of integers we // require, cause an exception. else if (data.size != size) throw IllegalArgumentException( "Bad input!") // Add the line to the matrix. matrix.add(data) } // while // Read the list of index substitutions. // Read the line, split it by spaces, // and convert the string to an integer. // Cause an exception on end of file, // non integer data, not having the // number of integers we require, our // minimum value not being zero, our // maximum value not being one less // than our size, and converting to // a set (to lose duplicates) we lost // elements. val data = readLine()!!.split(" ").map { it.toInt() } if (data.size != size || data.min() != 0 || data.max() != size-1 || data.toSet().size != size) throw IllegalArgumentException( "Bad list!") // Every thing checked out so we can // process the user's request. process(matrix.toList(), data) // On exception, complain and process our // test case examples from the challenge. } catch (error: Throwable) { println("Bad input using defaults!") process(listOf(listOf(11, 21, 31), listOf( 12, 22, 32), listOf(13, 23, 33)), listOf(2, 0, 1)) process(listOf(listOf(35, 1, 6, 26, 19, 24), listOf(3, 32, 7, 21, 23, 25), listOf(31, 9, 2, 22, 27, 20), listOf(8, 28, 33, 17, 10, 15), listOf(30, 5, 34, 12, 14, 16), listOf(4, 36, 29, 13, 18, 11)), listOf( 2, 4, 5, 0, 3, 1)) } // try } // main

reorder cg