1 files changed, 18 insertions, 29 deletions

diff --git a/extern/ceres/include/ceres/ordered_groups.h b/extern/ceres/include/ceres/ordered_groups.h
index aa1bd3a7da1..954663c97e6 100644
--- a/extern/ceres/include/ceres/ordered_groups.h
+++ b/extern/ceres/include/ceres/ordered_groups.h
@@ -1,5 +1,5 @@
 // Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2015 Google Inc. All rights reserved.
+// Copyright 2019 Google Inc. All rights reserved.
 // http://ceres-solver.org/
 //
 // Redistribution and use in source and binary forms, with or without
@@ -33,7 +33,9 @@
 
 #include <map>
 #include <set>
+#include <unordered_map>
 #include <vector>
+
 #include "ceres/internal/port.h"
 #include "glog/logging.h"
 
@@ -63,8 +65,7 @@ class OrderedGroups {
       return false;
     }
 
-    typename std::map<T, int>::const_iterator it =
-        element_to_group_.find(element);
+    auto it = element_to_group_.find(element);
     if (it != element_to_group_.end()) {
       if (it->second == group) {
         // Element is already in the right group, nothing to do.
@@ -126,17 +127,14 @@ class OrderedGroups {
       return;
     }
 
-    typename std::map<int, std::set<T> >::reverse_iterator it =
-        group_to_elements_.rbegin();
-    std::map<int, std::set<T> > new_group_to_elements;
+    auto it = group_to_elements_.rbegin();
+    std::map<int, std::set<T>> new_group_to_elements;
     new_group_to_elements[it->first] = it->second;
 
     int new_group_id = it->first + 1;
     for (++it; it != group_to_elements_.rend(); ++it) {
-      for (typename std::set<T>::const_iterator element_it = it->second.begin();
-           element_it != it->second.end();
-           ++element_it) {
-        element_to_group_[*element_it] = new_group_id;
+      for (const auto& element : it->second) {
+        element_to_group_[element] = new_group_id;
       }
       new_group_to_elements[new_group_id] = it->second;
       new_group_id++;
@@ -148,8 +146,7 @@ class OrderedGroups {
   // Return the group id for the element. If the element is not a
   // member of any group, return -1.
   int GroupId(const T element) const {
-    typename std::map<T, int>::const_iterator it =
-        element_to_group_.find(element);
+    auto it = element_to_group_.find(element);
     if (it == element_to_group_.end()) {
       return -1;
     }
@@ -157,27 +154,21 @@ class OrderedGroups {
   }
 
   bool IsMember(const T element) const {
-    typename std::map<T, int>::const_iterator it =
-        element_to_group_.find(element);
+    auto it = element_to_group_.find(element);
     return (it != element_to_group_.end());
   }
 
   // This function always succeeds, i.e., implicitly there exists a
   // group for every integer.
   int GroupSize(const int group) const {
-    typename std::map<int, std::set<T> >::const_iterator it =
-        group_to_elements_.find(group);
-    return (it ==  group_to_elements_.end()) ? 0 : it->second.size();
+    auto it = group_to_elements_.find(group);
+    return (it == group_to_elements_.end()) ? 0 : it->second.size();
   }
 
-  int NumElements() const {
-    return element_to_group_.size();
-  }
+  int NumElements() const { return element_to_group_.size(); }
 
   // Number of groups with one or more elements.
-  int NumGroups() const {
-    return group_to_elements_.size();
-  }
+  int NumGroups() const { return group_to_elements_.size(); }
 
   // The first group with one or more elements. Calling this when
   // there are no groups with non-zero elements will result in a
@@ -187,17 +178,15 @@ class OrderedGroups {
     return group_to_elements_.begin()->first;
   }
 
-  const std::map<int, std::set<T> >& group_to_elements() const {
+  const std::map<int, std::set<T>>& group_to_elements() const {
     return group_to_elements_;
   }
 
-  const std::map<T, int>& element_to_group() const {
-    return element_to_group_;
-  }
+  const std::map<T, int>& element_to_group() const { return element_to_group_; }
 
  private:
-  std::map<int, std::set<T> > group_to_elements_;
-  std::map<T, int> element_to_group_;
+  std::map<int, std::set<T>> group_to_elements_;
+  std::unordered_map<T, int> element_to_group_;
 };
 
 // Typedef for the most commonly used version of OrderedGroups.