diff --git a/lib/core/segments.js b/lib/core/segments.js
index ba8be178..43dbfd2b 100644
--- a/lib/core/segments.js
+++ b/lib/core/segments.js
@@ -202,12 +202,12 @@ function buildGraph (nodes, version) {
             getSegmentBitsLength(table[prevNodeId].lastCount + node.length, node.mode) -
             getSegmentBitsLength(table[prevNodeId].lastCount, node.mode)
 
-          table[prevNodeId].lastCount += node.length
+          table[key].lastCount += node.length
         } else {
-          if (table[prevNodeId]) table[prevNodeId].lastCount = node.length
-
           graph[prevNodeId][key] = getSegmentBitsLength(node.length, node.mode) +
             4 + Mode.getCharCountIndicator(node.mode, version) // switch cost
+
+          table[key].lastCount = node.length
         }
       }
     }