From 9caa616910f339471f13322872fd5e8104928248 Mon Sep 17 00:00:00 2001
From: Felix Salfelder <felix@salfelder.org>
Date: Tue, 28 Jun 2016 22:58:32 +0100
Subject: [PATCH] tighten check on edges in decomposition tree

according to spec, the first vertex number must be the small one.
---
 td-validate.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/td-validate.cpp b/td-validate.cpp
index dce7f73..8cef839 100644
--- a/td-validate.cpp
+++ b/td-validate.cpp
@@ -418,7 +418,7 @@ void read_decomp_edge(const std::vector<std::string>& tokens, tree_decomposition
 
   unsigned s = pure_stou(tokens[0]);
   unsigned d = pure_stou(tokens[1]);
-  if(s < 1 || d < 1 || s > n_decomp || d > n_decomp) {
+  if(s < 1 || d <= s || d > n_decomp) {
     throw std::invalid_argument(INV_EDGE);
   }
   T.add_edge(s-1, d-1);