Should fix auc I think

Author: Immaterial0

src/auc.cpp

@@ -109,10 +109,8 @@ List auc(
     FPR[i] /= n0;
     FNR[i] /= n1;
 
-    if (i == 0)
-      continue;
-    
-    auc += (TPR[i] + TPR[i - 1])*(FPR[i - 1] - FPR[i])/2.0;
+    if (i == 0) auc += (1+TPR[0])*(1 - FPR[0])/2.0;
+    else auc += (TPR[i] + TPR[i - 1])*(FPR[i - 1] - FPR[i])/2.0;
 
   }