Interval tree initial commit

Author: mgechev

src/data-structures/interval-tree.js

@@ -0,0 +1,47 @@
+function Node(start, end, left, right) {
+  this.interval = [start, end];
+  this.maxRight = -Infinity;
+  this.parentNode = null;
+  this.left = left;
+  this.right = right;
+}
+
+function IntervalTree() {
+  this.root = null;
+}
+
+function addNode(node, side, interval) {
+  var child = new Node(interval[0], interval[1]);
+  child.parentNode = node;
+  node[side] = child;
+  if (side === 'right' && node.maxRight < interval[1]) {
+    while (child) {
+      child.maxRight = interval[1];
+      child = child.parentNode;
+    }
+  }
+}
+
+function addHelper(node, interval) {
+  if (node.interval[0] > interval[0]) {
+    if (node.left) {
+      addHelper(node.left, interval);
+    } else {
+      addNode(node, 'left', interval);
+    }
+  } else {
+    if (node.right) {
+      addHelper(node.right, interval);
+    } else {
+      addNode(node, 'right', interval);
+    }
+  }
+}
+
+IntervalTree.prototype.add = function (interval) {
+  if (!this.root) {
+    this.root = new Node(interval[0], interval[1]);
+    return;
+  }
+  addHelper(this.root, interval);
+};