Data update

Task/Balanced-brackets/Pluto/balanced-brackets.pluto

@@ -0,0 +1,36 @@
+local function is_balanced(s)
+    if s == "" then
+        return true
+    end
+    local counter_left = 0  -- number of left brackets so far unmatched
+    for i = 1, #s do
+        local c = s[i]
+        if c == "[" then
+            counter_left += 1
+        elseif counter_left > 0 do
+            counter_left -= 1
+        else
+            return false
+        end
+    end
+    return counter_left == 0
+end
+
+print("Checking examples in task description:")
+local brackets = {"", "[]", "][", "[][]", "][][", "[[][]]", "[]][[]"}
+for brackets as b do
+    local res = is_balanced(b)
+    local bb = (b != "") ? b : "(empty)"
+    print(string.format("%-8s  %s", bb, res ? "OK" : "NOT OK"))
+end
+
+print("\nChecking 7 random strings of brackets of length 8:")
+math.randomseed(os.time())
+for i = 1, 7 do
+    local b = ""
+    for j = 1, 8 do
+        b ..= (math.random(0, 1) == 0) ? "[" : "]"
+    end
+    local res = is_balanced(b)
+    print(string.format("%s  %s", b, res ? "OK" : "NOT OK"))
+end