[PWGJE] Change to a more efficient way of selecting particle tracks (#12686)

Author: ynishida-style

PWGJE/Tasks/jetShape.cxx

@@ -268,37 +268,46 @@ struct JetShapeTask {
 
     registry.fill(HIST("event/vertexz"), collision.posZ());
 
+    std::vector<typename std::decay_t<decltype(tracks)>::iterator> goodTracks;
+    for (auto it = tracks.begin(); it != tracks.end(); ++it) {
+      const auto& track = *it;
+
+      registry.fill(HIST("trackTpcNClsCrossedRows"), track.tpcNClsCrossedRows());
+      registry.fill(HIST("trackDcaXY"), track.dcaXY());
+      registry.fill(HIST("trackItsChi2NCl"), track.itsChi2NCl());
+      registry.fill(HIST("trackTpcChi2NCl"), track.tpcChi2NCl());
+      registry.fill(HIST("trackTpcNClsFound"), track.tpcNClsFound());
+      registry.fill(HIST("trackItsNCls"), track.itsNCls());
+      registry.fill(HIST("trackEta"), track.eta());
+      registry.fill(HIST("trackPhi"), track.phi());
+
+      if (std::abs(track.eta()) > etaTrUp)
+        continue;
+      if (track.tpcNClsCrossedRows() < nclcrossTpcMin)
+        continue;
+      if (std::abs(track.dcaXY()) > dcaxyMax)
+        continue;
+      if (track.itsChi2NCl() > chi2ItsMax)
+        continue;
+      if (track.tpcChi2NCl() > chi2TpcMax)
+        continue;
+      if (track.tpcNClsFound() < nclTpcMin)
+        continue;
+      if (track.itsNCls() < nclItsMin)
+        continue;
+
+      goodTracks.push_back(it);
+    }
+
     for (auto const& jet : jets) {
       if (!isAcceptedJet<aod::JetTracks>(jet)) {
         continue;
       }
 
       // tracks conditions
-      for (const auto& track : tracks) {
+      for (const auto& track_it : goodTracks) {
 
-        registry.fill(HIST("trackTpcNClsCrossedRows"), track.tpcNClsCrossedRows());
-        registry.fill(HIST("trackDcaXY"), track.dcaXY());
-        registry.fill(HIST("trackItsChi2NCl"), track.itsChi2NCl());
-        registry.fill(HIST("trackTpcChi2NCl"), track.tpcChi2NCl());
-        registry.fill(HIST("trackTpcNClsFound"), track.tpcNClsFound());
-        registry.fill(HIST("trackItsNCls"), track.itsNCls());
-        registry.fill(HIST("trackEta"), track.eta());
-        registry.fill(HIST("trackPhi"), track.phi());
-
-        if (std::abs(track.eta()) > etaTrUp)
-          continue;
-        if (track.tpcNClsCrossedRows() < nclcrossTpcMin)
-          continue;
-        if (std::abs(track.dcaXY()) > dcaxyMax)
-          continue;
-        if (track.itsChi2NCl() > chi2ItsMax)
-          continue;
-        if (track.tpcChi2NCl() > chi2TpcMax)
-          continue;
-        if (track.tpcNClsFound() < nclTpcMin)
-          continue;
-        if (track.itsNCls() < nclItsMin)
-          continue;
+        const auto& track = *track_it;
 
         // PID check
         registry.fill(HIST("tofMass"), track.mass());