Data commit

Task/Balanced-brackets/Groovy/balanced-brackets-1.groovy

@@ -0,0 +1,21 @@
+def random = new Random()
+
+def factorial = { (it > 1) ? (2..it).inject(1) { i, j -> i*j } : 1 }
+
+def makePermutation;
+makePermutation = { string, i ->
+    def n = string.size()
+    if (n < 2) return string
+    def fact = factorial(n-1)
+    assert i < fact*n
+
+    def index = i.intdiv(fact)
+    string[index] + makePermutation(string[0..<index] + string[(index+1)..<n], i % fact)
+}
+
+def randomBrackets = { n ->
+    if (n == 0) return ''
+    def base = '['*n + ']'*n
+    def p = random.nextInt(factorial(n*2))
+    makePermutation(base, p)
+}

Task/Balanced-brackets/Groovy/balanced-brackets-2.groovy

@@ -0,0 +1,11 @@
+boolean balancedBrackets(String brackets, int depth=0) {
+    if (brackets == null || brackets.empty) return depth == 0
+    switch (brackets[0]) {
+        case '[':
+            return brackets.size() > 1  &&  balancedBrackets(brackets[1..-1], depth + 1)
+        case ']':
+            return depth > 0  &&  (brackets.size() == 1  ||  balancedBrackets(brackets[1..-1], depth - 1))
+        default:
+            return brackets.size() == 1  ?  depth == 0  :  balancedBrackets(brackets[1..-1], depth)
+    }
+}

Task/Balanced-brackets/Groovy/balanced-brackets-3.groovy

@@ -0,0 +1,13 @@
+Set brackets = []
+(0..100).each {
+    (0..8).each { r ->
+        brackets << randomBrackets(r)
+    }
+}
+
+brackets.sort { a, b ->
+    a.size() <=> b.size() ?: a <=> b
+} .each {
+    def bal = balancedBrackets(it) ? "balanced:   " : "unbalanced: "
+    println "${bal} ${it}"
+}