Add insertIntoSortedArray utility function

Uses binary search to insert an element into a sorted array in logN time

Author: Eunovo

src/sortutils.d.ts

@@ -0,0 +1,9 @@
+/**
+ * Inserts an element into a sorted array.
+ * @template T
+ * @param {Array<T>} array - The sorted array to insert into.
+ * @param {T} element - The element to insert.
+ * @param {(a: T, b: T) => number} compare - The comparison function used to sort the array.
+ * @returns {number} The index at which the element was inserted.
+ */
+export declare function insertIntoSortedArray<T>(array: Array<T>, element: T, compare: (a: T, b: T) => number): number;

src/sortutils.js

@@ -0,0 +1,58 @@
+'use strict';
+Object.defineProperty(exports, '__esModule', { value: true });
+exports.insertIntoSortedArray = void 0;
+/**
+ * Inserts an element into a sorted array.
+ * @template T
+ * @param {Array<T>} array - The sorted array to insert into.
+ * @param {T} element - The element to insert.
+ * @param {(a: T, b: T) => number} compare - The comparison function used to sort the array.
+ * @returns {number} The index at which the element was inserted.
+ */
+function insertIntoSortedArray(array, element, compare) {
+  let high = array.length - 1;
+  let low = 0;
+  let mid;
+  let highElement, lowElement, midElement;
+  let compareHigh, compareLow, compareMid;
+  let targetIndex;
+  while (targetIndex === undefined) {
+    if (high < low) {
+      targetIndex = low;
+      continue;
+    }
+    mid = Math.floor((low + high) / 2);
+    highElement = array[high];
+    lowElement = array[low];
+    midElement = array[mid];
+    compareHigh = compare(element, highElement);
+    compareLow = compare(element, lowElement);
+    compareMid = compare(element, midElement);
+    if (low === high) {
+      // Target index is either to the left or right of element at low
+      if (compareLow <= 0) targetIndex = low;
+      else targetIndex = low + 1;
+      continue;
+    }
+    if (compareHigh >= 0) {
+      // Target index is to the right of high
+      low = high;
+      continue;
+    }
+    if (compareLow <= 0) {
+      // Target index is to the left of low
+      high = low;
+      continue;
+    }
+    if (compareMid <= 0) {
+      // Target index is to the left of mid
+      high = mid;
+      continue;
+    }
+    // Target index is to the right of mid
+    low = mid + 1;
+  }
+  array.splice(targetIndex, 0, element);
+  return targetIndex;
+}
+exports.insertIntoSortedArray = insertIntoSortedArray;

ts_src/sortutils.ts

@@ -0,0 +1,66 @@
+/**
+ * Inserts an element into a sorted array.
+ * @template T
+ * @param {Array<T>} array - The sorted array to insert into.
+ * @param {T} element - The element to insert.
+ * @param {(a: T, b: T) => number} compare - The comparison function used to sort the array.
+ * @returns {number} The index at which the element was inserted.
+ */
+export function insertIntoSortedArray<T>(
+  array: Array<T>,
+  element: T,
+  compare: (a: T, b: T) => number,
+) {
+  let high = array.length - 1;
+  let low = 0;
+  let mid;
+  let highElement, lowElement, midElement;
+  let compareHigh, compareLow, compareMid;
+  let targetIndex;
+  while (targetIndex === undefined) {
+    if (high < low) {
+      targetIndex = low;
+      continue;
+    }
+
+    mid = Math.floor((low + high) / 2);
+
+    highElement = array[high];
+    lowElement = array[low];
+    midElement = array[mid];
+
+    compareHigh = compare(element, highElement);
+    compareLow = compare(element, lowElement);
+    compareMid = compare(element, midElement);
+
+    if (low === high) {
+      // Target index is either to the left or right of element at low
+      if (compareLow <= 0) targetIndex = low;
+      else targetIndex = low + 1;
+      continue;
+    }
+
+    if (compareHigh >= 0) {
+      // Target index is to the right of high
+      low = high;
+      continue;
+    }
+    if (compareLow <= 0) {
+      // Target index is to the left of low
+      high = low;
+      continue;
+    }
+
+    if (compareMid <= 0) {
+      // Target index is to the left of mid
+      high = mid;
+      continue;
+    }
+
+    // Target index is to the right of mid
+    low = mid + 1;
+  }
+
+  array.splice(targetIndex, 0, element);
+  return targetIndex;
+}