Fix minor grammar mistake

content/blog/01_cs325_languages_hw2.md

@@ -81,7 +81,7 @@ which has access to the variables below:
 * `LSTATE` and `RSTATE`, to denote the final states from the two subproblems.
 
 We use an `if`-statement to check if the element that was popped came
-from the right list (by checking `SOURCE == R`). If it is, we increment the counter
+from the right list (by checking `SOURCE == R`). If it did, we increment the counter
 (state) by the proper amount. In the combine step, which has access to the
 same variables, we simply increment the state by the counters from the left
 and right solutions, stored in `LSTATE` and `RSTATE`. That's it!