diff --git a/src/main/java/sugui/Day05.java b/src/main/java/sugui/Day05.java
index 55388ed..fad5bd3 100644
--- a/src/main/java/sugui/Day05.java
+++ b/src/main/java/sugui/Day05.java
@@ -24,13 +24,13 @@ public class Day05 {
     private record ProductionKitRanged(List<Pair<Long, Long>> seedPairs, List<List<MapInfo>> maps) {
     }
 
-    private record MapInfo(long destination, long source, long range) {
+    public record MapInfo(long destination, long source, long range) {
     }
 
-    private static long getLocation(List<MapInfo> mapper, long origin) {
+    public static long getLocation(List<MapInfo> mapper, long origin) {
         for (var mapInfo : mapper) {
             var originSourceDiff = origin - mapInfo.source;
-            if (originSourceDiff >= 0 && originSourceDiff <= mapInfo.range)
+            if (originSourceDiff >= 0 && originSourceDiff < mapInfo.range)
                 return mapInfo.destination + originSourceDiff;
         }
         return origin;
@@ -103,7 +103,9 @@ public class Day05 {
         ProductionKitRanged prodKit = parseSecond(input);
         long minLocation = Long.MAX_VALUE;
         for (var seedPair : prodKit.seedPairs) {
-            for (long seed = seedPair._1(); seed < seedPair._1() + seedPair._2(); seed++) {
+            long initSeed = seedPair._1();
+            long maxSeed = initSeed + seedPair._2();
+            for (long seed = initSeed; seed < maxSeed; seed++) {
                 long currLocation = seed;
                 for (var map : prodKit.maps) {
                     long newLocation = getLocation(map, currLocation);
diff --git a/src/main/java/sugui/util/Interval.java b/src/main/java/sugui/util/Interval.java
index f757480..7375a6e 100644
--- a/src/main/java/sugui/util/Interval.java
+++ b/src/main/java/sugui/util/Interval.java
@@ -2,15 +2,19 @@ package sugui.util;
 
 import java.util.Iterator;
 import java.util.LinkedList;
+import java.util.ListIterator;
 
 /**
  * Class for intervals. From is inclusive, to is exclusive.
  */
-public class Interval {
+public class Interval implements Iterable<Long> {
     private record Node(long value, boolean canBeLess) {
     }
+
     LinkedList<Node> interval = new LinkedList<>();
 
+    private Interval() {}
+
     public Interval(long from, long to) {
         Node fromNode = new Node(from, false);
         Node toNode = new Node(to, true);
@@ -19,13 +23,68 @@ public class Interval {
     }
 
     public boolean contains(long x) {
-        Iterator<Node> iterator = interval.iterator();
-        while(iterator.hasNext()) {
-            Node currNode = iterator.next();
-            if (x < currNode.value) {
-                return currNode.canBeLess;
+        for (Node node : interval) {
+            if (x < node.value) {
+                return node.canBeLess;
             }
         }
         return false;
     }
+
+    private void addNode(Node node) {
+        ListIterator<Node> iterator = interval.listIterator();
+        while (iterator.hasNext()) {
+            Node currNode = iterator.next();
+            if (node.value < currNode.value) {
+                iterator.previous();
+                iterator.add(node);
+                return;
+            }
+        }
+        iterator.add(node);
+    }
+
+    /**
+     * Adds the external interval to the current interval, modifying it.
+     * @param extInterval the inverval to add to the current interval
+     */
+    public Interval union(Interval extInterval) {
+        Interval toret = new Interval();
+        for (Node node : interval) {
+            toret.addNode(node);
+        }
+        for (Node node : extInterval.interval) {
+            toret.addNode(node);
+        }
+        toret.normalize();
+        return toret;
+    }
+
+    public void normalize() {
+        ListIterator<Node> iterator = interval.listIterator();
+        while (iterator.hasNext()) {
+            Node currNode = iterator.next();
+            if (iterator.hasNext()) {
+                Node nextNode = iterator.next();
+                iterator.previous();
+                if (currNode.value == nextNode.value) {
+                    iterator.remove();
+                }            
+            }
+        }
+    }
+
+    @Override
+    public Iterator<Long> iterator() {
+        return new IntervalIterator(this);
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder stringBuilder = new StringBuilder();
+        for (Node node : interval) {
+            stringBuilder.append(node.canBeLess + " < " + node.value + "\n");
+        }
+        return stringBuilder.toString();
+    }
 }
diff --git a/src/main/java/sugui/util/IntervalIterator.java b/src/main/java/sugui/util/IntervalIterator.java
new file mode 100644
index 0000000..d199168
--- /dev/null
+++ b/src/main/java/sugui/util/IntervalIterator.java
@@ -0,0 +1,22 @@
+package sugui.util;
+
+import java.util.Iterator;
+
+public class IntervalIterator implements Iterator<Long> {
+    private Interval interval;
+    public IntervalIterator(Interval interval) {
+        this.interval = interval;
+    }
+
+    @Override
+    public boolean hasNext() {
+        // TODO Auto-generated method stub
+        return false;
+    }
+
+    @Override
+    public Long next() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+}
diff --git a/src/test/java/sugui/Day05Test.java b/src/test/java/sugui/Day05Test.java
index 2040ec1..4de412c 100644
--- a/src/test/java/sugui/Day05Test.java
+++ b/src/test/java/sugui/Day05Test.java
@@ -3,6 +3,7 @@ package sugui;
 import static org.junit.Assert.assertEquals;
 
 import java.io.IOException;
+import java.util.List;
 
 import org.junit.Test;
 
@@ -56,6 +57,13 @@ public class Day05Test {
         assertEquals(firstBasicResult, actualResult);
     }
 
+    @Test
+    public void isGetLocationExclusive() {
+        assertEquals(Day05.getLocation(List.of(
+                new Day05.MapInfo(30, 0, 2)), 2),
+                2);
+    }
+
     @Test
     public void secondBasicCase() throws IOException {
         String actualResult = Day05.getSecondPuzzleResult(secondBasicInput);
diff --git a/src/test/java/sugui/IntervalTest.java b/src/test/java/sugui/IntervalTest.java
index 7db3d67..0be5ec1 100644
--- a/src/test/java/sugui/IntervalTest.java
+++ b/src/test/java/sugui/IntervalTest.java
@@ -15,15 +15,28 @@ import sugui.util.Interval;
  */
 public class IntervalTest {
 
-    public static Interval interval1 = new Interval(2, 8);
+    public static Interval interval1 = new Interval(2, 4);
+    public static Interval interval2 = new Interval(7, 9);
+    public static Interval union = interval1.union(interval2);
 
     @Test
-    public void containsTest() throws IOException {
+    public void containsTest() {
         assertTrue(interval1.contains(2));
-        assertTrue(interval1.contains(5));
-        assertTrue(interval1.contains(7));
+        assertTrue(interval1.contains(3));
         assertFalse(interval1.contains(1));
         assertFalse(interval1.contains(8));
         assertFalse(interval1.contains(10));
     }
+
+    @Test
+    public void unionTest() {
+        assertTrue(union.contains(2));
+        assertTrue(union.contains(3));
+        assertFalse(union.contains(4));
+        assertFalse(union.contains(5));
+        assertFalse(union.contains(6));
+        assertTrue(union.contains(7));
+        assertTrue(union.contains(8));
+        assertFalse(union.contains(9));
+    }
 }