Update intro-to-dp.md

Someone added the r to memoization despite the beginning of the article literally mentioning not to do this 😔.😂

src/dynamic_programming/intro-to-dp.md

@@ -81,7 +81,7 @@ $$\text{work per subproblem} * \text{number of subproblems}$$
 
 Using a binary search tree (map in C++) to save states will technically result in $O(n \log n)$ as each lookup and insertion will take $O(\log n)$ work and with $O(n)$ unique subproblems we have $O(n \log n)$ time.
 
-This approach is called top-down, as we can call the function with a query value and the calculation starts going from the top (queried value) down to the bottom (base cases of the recursion), and makes shortcuts via memorization on the way.
+This approach is called top-down, as we can call the function with a query value and the calculation starts going from the top (queried value) down to the bottom (base cases of the recursion), and makes shortcuts via memoization on the way.
 
 ## Bottom-up Dynamic Programming