Fix topological sort

Signed-off-by: Bruno Freitas Tissei <bft15@inf.ufpr.br>

algorithms/graph/topological_sort.cpp

@@ -8,29 +8,29 @@ vector<int> graph[MAX];
 struct TopologicalSort {
   int N;
   stack<int> S;
-  vector<int> cont;
+  vector<int> vis;
 
-  Topological(int N) :
-    N(N), cont(N)
+  TopologicalSort(int N) :
+    N(N), vis(N)
   {}
 
   void init() {
-    fill(all(cont), 0);
+    fill(all(vis), 0);
   }
 
   /// Fills stack and check for cycles.
   /// @param x any vertex
   bool dfs(int x) {
-    cont[x] = 1;
+    vis[x] = 1;
 
     for (auto i : graph[x]) {
-      if (cont[i] == 1)
+      if (vis[i] == 1)
         return true;
-      if (!cont[i] && dfs(i))
+      if (!vis[i] && dfs(i))
         return true;
     }
 
-    cont[x] = 2;
+    vis[x] = 2;
     S.push(x);
 
     return false;
@@ -43,7 +43,7 @@ struct TopologicalSort {
 
     bool cycle = false;
     for (int i = 0; i < N; ++i) {
-      if (!cont[i])
+      if (!vis[i])
         cycle |= dfs(i);
     }