[AD] Fixes #1

semester1/algorithms-and-datastructures/parts/intro.tex

@@ -5,13 +5,13 @@
 \begin{definition}[]{Sufficiency}
     A condition $P$ is called \textit{sufficient} for $Q$ if knowing $P$ is true is enough evidence to conclude that $Q$ is true.
 
-    This is equivalent to saying $Q \Rightarrow P$.
+    This is equivalent to saying $P \Rightarrow Q$.
 \end{definition}
 
 \begin{definition}[]{Necessity}
     A condition $P$ is called \textit{necessary} for $Q$ if $Q$ cannot occur unless $P$ is true, but doesn't imply that $Q$ is true, only that it is false if $P$ is false.
 
-    This is equivalent to saying $P \Rightarrow Q$
+    This is equivalent to saying $Q \Rightarrow P$
 \end{definition}
 
 \subsection{Asymptotic Growth}