Update 2SAT.md

Sarthak3204 · web-flow · commit ca045b933ad0 · 2024-05-11T22:45:33.000+05:30
Added Codeforces 2SAT question
diff --git a/src/graph/2SAT.md b/src/graph/2SAT.md
@@ -168,3 +168,4 @@ void add_disjunction(int a, bool na, int b, bool nb) {
  * [UVA: Rectangles](https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=3081)
  * [Codeforces : Radio Stations](https://codeforces.com/problemset/problem/1215/F)
  * [CSES : Giant Pizza](https://cses.fi/problemset/task/1684)
+ * [Codeforces: +-1](https://codeforces.com/contest/1971/problem/H)
