smarter joinable algo

server/src/zone.rs

@@ -208,11 +208,8 @@ pub fn node_joinable(graph: &ZoneGraph, target_index: NodeIndex) -> bool {
         }
     }
 
-    // now check the graph for connectedness
-    // get all the nodes that have been successfully completed
-    let mut filtered = graph.clone();
-    filtered.retain_nodes(|g, i| {
-        match g.node_weight(i) {
+    let success_indices = graph.node_indices().filter(|i| {
+        match graph.node_weight(*i) {
            Some(encounter) => encounter.success,
            None => panic!("no weight for {:?}", i),
         }
@@ -221,7 +218,7 @@ pub fn node_joinable(graph: &ZoneGraph, target_index: NodeIndex) -> bool {
     // if a node is a neighbour of that graph
     // and hasn't been attempted
     // it is joinable
-    for i in filtered.node_indices() {
+    for i in success_indices {
         match graph.neighbors(i).find(|n| *n == target_index) {
             Some(_n) => return true,
             None => continue,