Initial data commit

Task/Balanced-brackets/D/balanced-brackets-3.d

@@ -0,0 +1,19 @@
+import std.stdio, std.random, std.range, std.algorithm;
+
+bool isBalanced(in string s, in char[2] pars="[]") pure nothrow @safe @nogc {
+    bool bal(in string t, in int nb = 0) pure nothrow @safe @nogc {
+        if (!nb && t.empty) return true;
+        if (t.empty || nb < 0) return false;
+        if (t[0] == pars[0]) return bal(t.dropOne, nb + 1);
+        if (t[0] == pars[1]) return bal(t.dropOne, nb - 1);
+        return bal(t.dropOne, nb); // Ignore char.
+    }
+    return bal(s);
+}
+
+void main() {
+    foreach (immutable i; 1 .. 9) {
+        immutable s = iota(i * 2).map!(_ => "[]"[uniform(0, $)]).array;
+        writeln(s.isBalanced ? " OK " : "Bad ", s);
+    }
+}