new tasks

Task/Balanced_brackets/JavaScript/balanced_brackets.js

@@ -0,0 +1,43 @@
+function createRandomBracketSequence(maxlen)
+{
+   var chars = { '0' : '[' , '1' : ']' };
+   function getRandomInteger(to)
+   {
+      return Math.floor(Math.random() * (to+1));
+   }
+   var n = getRandomInteger(maxlen);
+   var result = [];
+   for(var i = 0; i < n; i++)
+   {
+     result.push(chars[getRandomInteger(1)]);
+   }
+   return result.join("");
+}
+
+function bracketsAreBalanced(s)
+{
+  var open = (arguments.length > 1) ? arguments[1] : '[';
+  var close = (arguments.length > 2) ? arguments[2] : ']';
+  var c = 0;
+  for(var i = 0; i < s.length; i++)
+  {
+    var ch = s.charAt(i);
+    if ( ch == open )
+    {
+      c++;
+    }
+    else if ( ch == close )
+    {
+      c--;
+      if ( c < 0 ) return false;
+    }
+  }
+  return c == 0;
+}
+
+var c = 0;
+while ( c < 5 ) {
+  var seq = createRandomBracketSequence(8);
+  alert(seq + ':\t' + bracketsAreBalanced(seq));
+  c++;
+}