From caf5bda249b11ba984da6bb9e2492e2ed2686fab Mon Sep 17 00:00:00 2001
From: Steven Proctor <steven.proctor@gmail.com>
Date: Sun, 11 Jan 2026 16:50:17 -0600
Subject: [PATCH] add next/prev values to ordered-range-value building

put the previous value on the start boundaries and a the next
value on the end boundaries
---
 src/challenge/discrete_value_range.clj       |  6 +-
 test/challenge/discrete_value_range_test.clj | 62 +++++++++++---------
 2 files changed, 38 insertions(+), 30 deletions(-)

diff --git a/src/challenge/discrete_value_range.clj b/src/challenge/discrete_value_range.clj
index 4c54463..31ea654 100644
--- a/src/challenge/discrete_value_range.clj
+++ b/src/challenge/discrete_value_range.clj
@@ -49,10 +49,12 @@
        (mapcat (fn [range]
                  [{:value (start range)
                    :boundary-type :start
-                   :type (range-type range)}
+                   :type (range-type range)
+                   :prev-value (value-before range)}
                   {:value (end range)
                    :boundary-type :end
-                   :type (range-type range)}]))
+                   :type (range-type range)
+                   :next-value (value-after range)}]))
        (sort-by (juxt :value (comp {:start 0 :end 1} :boundary-type)))))
 
 (defmulti ->discrete-value-range (fn [range-type _start _end]
diff --git a/test/challenge/discrete_value_range_test.clj b/test/challenge/discrete_value_range_test.clj
index 3b18a50..cbd3b31 100644
--- a/test/challenge/discrete_value_range_test.clj
+++ b/test/challenge/discrete_value_range_test.clj
@@ -64,22 +64,22 @@
 ;; test against integer ranges for easy of expression and interpretation
 (deftest ordered-range-values
   (testing "ordered range values are sorted by value and then the range's start boundary before any end boundary"
-    (is (= [{:value 1 :boundary-type :start :type :int-range-inclusive}
-            {:value 2 :boundary-type :end :type :int-range-inclusive}
-            {:value 4 :boundary-type :start :type :int-range-inclusive}
-            {:value 5 :boundary-type :start :type :int-range-inclusive}
-            {:value 5 :boundary-type :start :type :int-range-inclusive}
-            {:value 5 :boundary-type :end :type :int-range-inclusive}
-            {:value 5 :boundary-type :end :type :int-range-inclusive}
-            {:value 8 :boundary-type :end :type :int-range-inclusive}]
+    (is (= [{:value 1 :prev-value 0 :boundary-type :start :type :int-range-inclusive}
+            {:value 2 :next-value 3 :boundary-type :end :type :int-range-inclusive}
+            {:value 4 :prev-value 3 :boundary-type :start :type :int-range-inclusive}
+            {:value 5 :prev-value 4 :boundary-type :start :type :int-range-inclusive}
+            {:value 5 :prev-value 4 :boundary-type :start :type :int-range-inclusive}
+            {:value 5 :next-value 6 :boundary-type :end :type :int-range-inclusive}
+            {:value 5 :next-value 6 :boundary-type :end :type :int-range-inclusive}
+            {:value 8 :next-value 9 :boundary-type :end :type :int-range-inclusive}]
            (#'range/ordered-range-values [(int-range-inclusive 1 2)
                                           (int-range-inclusive 4 5)
                                           (int-range-inclusive 5 8)
                                           (int-range-inclusive 5 5)])))
-    (is (= [{:value 5 :boundary-type :start :type :int-range-inclusive}
-            {:value 5 :boundary-type :start :type :int-range-inclusive}
-            {:value 5 :boundary-type :end :type :int-range-inclusive}
-            {:value 5 :boundary-type :end :type :int-range-inclusive}]
+    (is (= [{:value 5 :prev-value 4 :boundary-type :start :type :int-range-inclusive}
+            {:value 5 :prev-value 4 :boundary-type :start :type :int-range-inclusive}
+            {:value 5 :next-value 6 :boundary-type :end :type :int-range-inclusive}
+            {:value 5 :next-value 6 :boundary-type :end :type :int-range-inclusive}]
            (#'range/ordered-range-values [(int-range-inclusive 5 5)
                                           (int-range-inclusive 5 5)])))))
 
@@ -136,12 +136,10 @@
                                           :range-source-type :filter-range
                                           :value 1
                                           :prev-value 0
-                                          :next-value 2
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :filter-range
                                           :value 4
-                                          :prev-value 3
                                           :next-value 5
                                           :type :int-range-inclusive}]))))
   (testing "only source-ranges"
@@ -149,28 +147,34 @@
            (range/walk-range-boundaries [{:boundary-type :start
                                           :range-source-type :source-range
                                           :value 1
+                                          :prev-value 0
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 5
+                                          :next-value 6
                                           :type :int-range-inclusive}])))
     (is (= #{(int-range-inclusive 1 5)
              (int-range-inclusive 11 15)}
            (range/walk-range-boundaries [{:boundary-type :start
                                           :range-source-type :source-range
                                           :value 1
+                                          :next-value 2
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 5
+                                          :prev-value 4
                                           :type :int-range-inclusive}
                                          {:boundary-type :start
                                           :range-source-type :source-range
                                           :value 11
+                                          :next-value 12
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 15
+                                          :prev-value 14
                                           :type :int-range-inclusive}]))))
   (testing "filter-ranges before source-ranges"
     (is (= #{(int-range-inclusive 11 15)}
@@ -178,41 +182,41 @@
                                           :range-source-type :filter-range
                                           :value 1
                                           :prev-value 0
-                                          :next-value 2
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :filter-range
-                                          :prev-value 4
                                           :value 5
                                           :next-value 6
                                           :type :int-range-inclusive}
                                          {:boundary-type :start
                                           :range-source-type :source-range
                                           :value 11
+                                          :prev-value 10
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 15
+                                          :next-value 16
                                           :type :int-range-inclusive}]))))
   (testing "filter-ranges after source-ranges"
     (is (= #{(int-range-inclusive 1 5)}
            (range/walk-range-boundaries [{:boundary-type :start
                                           :range-source-type :source-range
                                           :value 1
+                                          :prev-value 0
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 5
+                                          :next-value 6
                                           :type :int-range-inclusive}
                                          {:boundary-type :start
                                           :range-source-type :filter-range
                                           :prev-value 10
                                           :value 11
-                                          :next-value 12
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :filter-range
-                                          :prev-value 14
                                           :value 15
                                           :next-value 16
                                           :type :int-range-inclusive}]))))
@@ -222,22 +226,22 @@
            (range/walk-range-boundaries [{:boundary-type :start
                                           :range-source-type :source-range
                                           :value 1
+                                          :prev-value 0
                                           :type :int-range-inclusive}
                                          {:boundary-type :start
                                           :range-source-type :filter-range
                                           :prev-value 5
                                           :value 6
-                                          :next-value 7
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :filter-range
-                                          :prev-value 10
                                           :value 10
                                           :next-value 11
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 20
+                                          :next-value 21
                                           :type :int-range-inclusive}]))))
   (testing "multiple filter-ranges between source-range"
     (is (= #{(int-range-inclusive 1 5)
@@ -246,16 +250,15 @@
            (range/walk-range-boundaries [{:boundary-type :start
                                           :range-source-type :source-range
                                           :value 1
+                                          :prev-value 0
                                           :type :int-range-inclusive}
                                          {:boundary-type :start
                                           :range-source-type :filter-range
                                           :prev-value 5
                                           :value 6
-                                          :next-value 7
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :filter-range
-                                          :prev-value 10
                                           :value 10
                                           :next-value 11
                                           :type :int-range-inclusive}
@@ -263,17 +266,16 @@
                                           :range-source-type :filter-range
                                           :prev-value 12
                                           :value 13
-                                          :next-value 14
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :filter-range
-                                          :prev-value 18
                                           :value 19
                                           :next-value 20
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 20
+                                          :prev-value 19
                                           :type :int-range-inclusive}]))))
   (testing "source range between filter-range"
     (is (= #{}
@@ -281,27 +283,29 @@
                                           :range-source-type :filter-range
                                           :prev-value 1
                                           :value 1
-                                          :next-value 2
                                           :type :int-range-inclusive}
                                          {:boundary-type :start
                                           :range-source-type :source-range
                                           :value 6
+                                          :prev-value 5
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 10
+                                          :next-value 11
                                           :type :int-range-inclusive}
                                          {:boundary-type :start
                                           :range-source-type :source-range
                                           :value 13
+                                          :prev-value 12
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 19
+                                          :next-value 20
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :filter-range
-                                          :prev-value 19
                                           :value 20
                                           :next-value 21
                                           :type :int-range-inclusive}]))))
@@ -311,29 +315,31 @@
            (range/walk-range-boundaries [{:boundary-type :start
                                           :range-source-type :source-range
                                           :value 1
+                                          :prev-value 0
                                           :type :int-range-inclusive}
                                          {:boundary-type :start
                                           :range-source-type :filter-range
                                           :prev-value 4
                                           :value 5
-                                          :next-value 6
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 6
+                                          :next-value 7
                                           :type :int-range-inclusive}
                                          {:boundary-type :start
                                           :range-source-type :source-range
                                           :value 8
+                                          :prev-value 7
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :filter-range
-                                          :prev-value 9
                                           :value 10
                                           :next-value 11
                                           :type :int-range-inclusive}
                                          {:boundary-type :end
                                           :range-source-type :source-range
                                           :value 13
+                                          :next-value 14
                                           :type :int-range-inclusive}])))))