Data commit

Task/Random-Latin-squares/D/random-latin-squares.d

@@ -0,0 +1,73 @@
+import std.array;
+import std.random;
+import std.stdio;
+
+alias Matrix = int[][];
+
+void latinSquare(int n) {
+    if (n <= 0) {
+        writeln("[]");
+        return;
+    }
+
+    Matrix latin = uninitializedArray!Matrix(n, n);
+    foreach (row; latin) {
+        for (int i = 0; i < n; i++) {
+            row[i] = i;
+        }
+    }
+    // first row
+    latin[0].randomShuffle;
+
+    // middle row(s)
+    for (int i = 1; i < n - 1; i++) {
+        bool shuffled = false;
+
+        shuffling:
+        while (!shuffled) {
+            latin[i].randomShuffle;
+            for (int k = 0; k < i; k++) {
+                for (int j = 0; j < n; j++) {
+                    if (latin[k][j] == latin[i][j]) {
+                        continue shuffling;
+                    }
+                }
+            }
+            shuffled = true;
+        }
+    }
+
+    // last row
+    for (int j = 0; j < n; j++) {
+        bool[] used = uninitializedArray!(bool[])(n);
+        used[] = false;
+
+        for (int i = 0; i < n - 1; i++) {
+            used[latin[i][j]] = true;
+        }
+        for (int k = 0; k < n; k++) {
+            if (!used[k]) {
+                latin[n - 1][j] = k;
+                break;
+            }
+        }
+    }
+
+    printSquare(latin);
+}
+
+void printSquare(Matrix latin) {
+    foreach (row; latin) {
+        writeln(row);
+    }
+}
+
+void main() {
+    latinSquare(5);
+    writeln;
+
+    latinSquare(5);
+    writeln;
+
+    latinSquare(10);
+}