Implement nonrepeatedCharacter.js

nonrepeatedCharacter/nonrepeatedCharacter.js

@@ -6,6 +6,30 @@
  *   firstNonRepeatedCharacter('AACBDB'); // => 'C'
  */
 
-var firstNonRepeatedCharacter = function(string) {
-  // TODO: your solution here
+var firstNonRepeatedCharacter = function (string) {
+  // solution will have to be at least O(n) because you have to go through all characters
+  // in string before you know whether any character is repeated
+  if ( typeof string !== 'string' ) throw new Error('Must provide a string');
+  if ( string.length <= 0 ) throw new Error('String must be at least a character long');
+
+  var hash = {};
+  var len  = string.length;
+  var i;
+
+
+
+  for (i = 0; i < len; i += 1) {
+    if ( hash[ string[i] ] === void 0 ) {
+      hash[ string[i] ] = true;
+    } else if ( hash[ string[i] ] ) {
+      hash[ string[i] ] = false;
+    }
+  }
+
+  i = 0;
+  while ( !hash[ string[i] ] ) {
+    i += 1;
+  }
+
+  return string[i];
 };