bring in red black node

src/test/java/com/github/btrekkie/interval_tree/IntervalTree.java

@@ -0,0 +1,60 @@
+package com.github.btrekkie.interval_tree;
+
+/**
+ * An interval tree data structure, which supports adding or removing an interval and finding an arbitrary interval that
+ * contains a specified value.
+ */
+/* The interval tree is ordered in ascending order of the start an interval, with ties broken by the end of the
+ * interval.  Each node is augmented with the maximum ending value of an interval in the subtree rooted at the node.
+ */
+public class IntervalTree {
+    /** The root node of the tree. */
+    private IntervalTreeNode root = IntervalTreeNode.LEAF;
+
+    /** Adds the specified interval to this. */
+    public void addInterval(IntervalTreeInterval interval) {
+        root = root.insert(new IntervalTreeNode(interval), true, null);
+    }
+
+    /**
+     * Removes the specified interval from this, if it is present.
+     * @param interval The interval.
+     * @return Whether the interval was present.
+     */
+    public boolean removeInterval(IntervalTreeInterval interval) {
+        IntervalTreeNode node = root;
+        while (!node.isLeaf()) {
+            if (interval.start < node.interval.start) {
+                node = node.left;
+            } else if (interval.start > node.interval.start) {
+                node = node.right;
+            } else if (interval.end < node.interval.end) {
+                node = node.left;
+            } else if (interval.end > node.interval.end) {
+                node = node.right;
+            } else {
+                root = node.remove();
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns an aribtrary IntervalTreeInterval in this that contains the specified value.  Returns null if there is no
+     * such interval.
+     */
+    public IntervalTreeInterval findInterval(double value) {
+        IntervalTreeNode node = root;
+        while (!node.isLeaf()) {
+            if (value >= node.interval.start && value <= node.interval.end) {
+                return node.interval;
+            } else if (value <= node.left.maxEnd) {
+                node = node.left;
+            } else {
+                node = node.right;
+            }
+        }
+        return null;
+    }
+}