🐛 chore: clean TODO

README.md

@@ -324,10 +324,10 @@ xarray.permutations([1, 2, 3]);
 [removePath$]: https://github.com/nodef/extra-array/wiki/removePath$
 [count]: https://github.com/nodef/extra-array/wiki/count
 [countEach]: https://github.com/nodef/extra-array/wiki/countEach
-[min]: https://github.com/nodef/extra-array/wiki/min
-[minEntry]: https://github.com/nodef/extra-array/wiki/minEntry
-[max]: https://github.com/nodef/extra-array/wiki/max
-[maxEntry]: https://github.com/nodef/extra-array/wiki/maxEntry
+[minimum]: https://github.com/nodef/extra-array/wiki/minimum
+[minimumEntry]: https://github.com/nodef/extra-array/wiki/minimumEntry
+[maximum]: https://github.com/nodef/extra-array/wiki/maximum
+[maximumEntry]: https://github.com/nodef/extra-array/wiki/maximumEntry
 [range]: https://github.com/nodef/extra-array/wiki/range
 [rangeEntries]: https://github.com/nodef/extra-array/wiki/rangeEntries
 [slice]: https://github.com/nodef/extra-array/wiki/slice

TODO

@@ -1,97 +1,6 @@
-SORTS, IN PAIR
-
-Instead of mapFn, provide pair array to define sort mapping.
-selectionSort, insertionSort, bubbleSort, mergeSort, (are all stable?)
-quickSort, shellSort, radixSort, timSort, heapSort
-https://en.wikipedia.org/wiki/Sorting_algorithm
-https://www.npmjs.com/package/sort-algorithms-js
-https://dl.acm.org/doi/10.5555/1778580.1778601
-https://stackoverflow.com/questions/463105/in-place-radix-sort/474040#474040
-
-
-MINNTH, MAXNTH, SORTEDSLICE (ARRAYVIEW)
-
-Need only part of sorted array? [bag][nth] ...
-Selection algorithm: Quickselect
-https://stackoverflow.com/questions/34395680/what-is-the-fastest-way-to-find-nth-biggest-number-of-an-int-array
-https://www.geeksforgeeks.org/kth-smallestlargest-element-unsorted-array/
-
-
 PARSE, OTHERS
 - (fm, fc)?
 
 
 INDEX -VE
 - moveWithin
-
-
-OLD SORT ALGORITHMS
-
-/**
- * Arrange values in order!
- * @param x an array (updated!)
- * @param fc compare function (a, b)
- * @param fm map function (v, i, x)
- * @param fs swap function (x, i, j)
- * @returns x | x[i] ≤ x[j] ∀ i ≤ j
- */
-function bubbleSort$<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null, fs: SwapFunction<T> | null=null): T[] {
-  var fc = fc || COMPARE;
-  var fm = fm || IDENTITY;  // TODO: use map function
-  var fs = fs || swap$;
-  var X  = x.length;
-  for (var i=0; i<X-1; ++i) {
-    for (var j=i+1; j<X; ++j)
-      if (fc(x[i], x[j]) > 0) fs(x, i, j);
-  }
-  return x;
-}
-
-
-/**
- * Arrange values in order!
- * @param x an array (updated!)
- * @param fc compare function (a, b)
- * @param fm map function (v, i, x)
- * @param fs swap function (x, i, j)
- * @returns x | x[i] ≤ x[j] ∀ i ≤ j
- */
-function selectionSort$<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null, fs: SwapFunction<T> | null=null): T[] {
-  var fc = fc || COMPARE;
-  var fm = fm || IDENTITY;  // TODO: use map function
-  var fs = fs || swap$;
-  var X  = x.length;
-  for (var i=0; i<X-1; ++i) {
-    var l = i;
-    for (var j=i+1; j<X; ++j)
-      if (fc(x[l], x[j]) > 0) l = j;
-    fs(x, i, l);
-  }
-  return x;
-}
-
-
-// TODO: Check if this is correct!
-/**
- * Arrange values in order!
- * @param x an array (updated!)
- * @param fc compare function (a, b)
- * @param fm map function (v, i, x)
- * @param fs swap function (x, i, j)
- * @returns x | x[i] ≤ x[j] ∀ i ≤ j
- */
-function insertionSortOld$<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null, fs: SwapFunction<T> | null=null): T[] {
-  var fc = fc || COMPARE;
-  var fm = fm || IDENTITY;  // TODO: use map function
-  var fs = fs || swap$;     // TODO: use swap function
-  var X  = x.length;
-  for (var i=X-2; i>=0; --i) {
-    var xv = x[i], mv = x[i];
-    for (var j=i+1; j<X; j++) {
-      if (fc(mv, x[j]) <= 0) break;
-      x[j-1] = x[j];
-    }
-    x[j-1] = xv;
-  }
-  return x;
-}

package.json

@@ -1,6 +1,6 @@
 {
   "name": "extra-array",
-  "version": "4.0.1",
+  "version": "4.0.2",
   "description": "An array is a collection of values, stored contiguously.",
   "main": "index.js",
   "module": "index.mjs",

src/index.ts

@@ -673,10 +673,11 @@ export {countEach as countAs};  // DEPRECATED
  * @param fm map function (v, i, x)
  * @returns v | v ≤ vᵢ; vᵢ ∈ x
  */
-export function min<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): T {
+export function minimum<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): T {
   var i = searchMinimumValue(x, fc, fm);
   return x[i];
 }
+export {minimum as min};
 
 
 /**
@@ -686,10 +687,11 @@ export function min<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: Ma
  * @param fm map function (v, i, x)
  * @returns [min_index, min_value]
  */
-export function minEntry<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): [number, T] {
+export function minimumEntry<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): [number, T] {
   var i = searchMinimumValue(x, fc, fm);
   return [i, x[i]];
 }
+export {minimumEntry as minEntry};
 
 
 /**
@@ -699,10 +701,11 @@ export function minEntry<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, f
  * @param fm map function (v, i, x)
  * @returns v | v ≥ vᵢ; vᵢ ∈ x
  */
-export function max<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): T {
+export function maximum<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): T {
   var i = searchMaximumValue(x, fc, fm);
   return x[i];
 }
+export {maximum as max};
 
 
 /**
@@ -712,10 +715,11 @@ export function max<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: Ma
  * @param fm map function (v, i, x)
  * @returns [max_index, max_value]
  */
-export function maxEntry<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): [number, T] {
+export function maximumEntry<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): [number, T] {
   var i = searchMaximumValue(x, fc, fm);
   return [i, x[i]];
 }
+export {maximumEntry as maxEntry};
 
 
 /**
@@ -753,6 +757,62 @@ export function rangeEntries<T, U=T>(x: T[], fc: CompareFunction<T|U> | null=nul
   }
   return [[mi, mv], [ni, nv]];
 }
+
+
+/**
+ * Find smallest values.
+ * @param x an array
+ * @param n number of values
+ * @param fc compare function (a, b)
+ * @param fm map function (v, i, x)
+ * @returns n smallest values in ascending order
+ */
+export function minimums<T, U=T>(x: T[], n: number, fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): T[] {
+  var is = searchMinimumValues(x, n, fc, fm);
+  return is.map(i => x[i]);
+}
+
+
+/**
+ * Find smallest entries.
+ * @param x an array
+ * @param n number of values
+ * @param fc compare function (a, b)
+ * @param fm map function (v, i, x)
+ * @returns n smallest entries in ascending order
+ */
+export function minimumEntries<T, U=T>(x: T[], n: number, fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): [number, T][] {
+  var is = searchMinimumValues(x, n, fc, fm);
+  return is.map(i => [i, x[i]]);
+}
+
+
+/**
+ * Find largest values.
+ * @param x an array
+ * @param n number of values
+ * @param fc compare function (a, b)
+ * @param fm map function (v, i, x)
+ * @returns n largest values in descending order
+ */
+export function maximums<T, U=T>(x: T[], n: number, fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): T[] {
+  var is = searchMaximumValues(x, n, fc, fm);
+  return is.map(i => x[i]);
+}
+
+
+/**
+ * Find largest entries.
+ * @param x an array
+ * @param n number of values
+ * @param fc compare function (a, b)
+ * @param fm map function (v, i, x)
+ * @returns n largest entries in descending order
+ */
+export function maximumEntries<T, U=T>(x: T[], n: number, fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): [number, T][] {
+  var is = searchMaximumValues(x, n, fc, fm);
+  return is.map(i => [i, x[i]]);
+}
 // #endregion
 
 
@@ -1498,6 +1558,52 @@ export function searchMaximumValue<T, U=T>(x: T[], fc: CompareFunction<T|U> | nu
 }
 
 
+/**
+ * Find indices of minimum values.
+ * @param x an array
+ * @param n number of values
+ * @param fc compare function (a, b)
+ * @param fm map function (v, i, x)
+ * @returns indices of minimum values in ascending order
+ */
+export function searchMinimumValues<T, U=T>(x: T[], n: number, fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): number[] {
+  var fc = fc || COMPARE;
+  var fm = fm || IDENTITY;
+  var X  = x.length;
+  // Create a max heap of indices.
+  var IH = Math.min(n, X);
+  var ih = fromRange(0, IH);
+  buildMaxHeap$(ih, 0, IH, fc, i => fm(x[i], i, x), swapRaw$);
+  var wr = fm(x[ih[0]], ih[0], x);
+  // Search for minimum values, and update heap.
+  for (var i=n; i<X; ++i) {
+    var w = fm(x[i], i, x);
+    if (fc(w, wr) >= 0) continue;
+    ih[0] = i;
+    maxHeapify$(ih, 0, IH, 0, fc, i => fm(x[i], i, x), swapRaw$);
+    var wr = fm(x[ih[0]], ih[0], x);
+  }
+  // Sort max heap in ascending order.
+  ih.sort((i, j) => fc(fm(x[i], i, x), fm(x[j], j, x)));
+  return ih;
+}
+
+
+/**
+ * Find indices of maximum values.
+ * @param x an array
+ * @param n number of values
+ * @param fc compare function (a, b)
+ * @param fm map function (v, i, x)
+ * @returns indices of maximum values in descending order
+ */
+export function searchMaximumValues<T, U=T>(x: T[], n: number, fc: CompareFunction<T|U> | null=null, fm: MapFunction<T, T|U> | null=null): number[] {
+  var fc = fc || COMPARE;
+  var fd = (a: T|U, b: T|U) => -fc(a, b);
+  return searchMinimumValues(x, n, fd, fm);
+}
+
+
 /**
  * Find first index of an unsorted value.
  * @param x an array
@@ -3272,8 +3378,8 @@ function buildReverseMinHeap$<T, U=T>(x: T[], i: number, I: number, fc: CompareF
  */
 function reverseMinHeapify$<T, U=T>(x: T[], i: number, I: number, r: number, fc: CompareFunction<T|U>, fm: MapFunction<T, T|U>, fs: SwapFunction<T>): void {
   var s  = r;         // Index of smallest value
-  var lt = 2*r - I;   // Reverse of lt = 2*r+1
-  var rt = lt  - 1;   // Reverse of rt = 2*r+2
+  var lt = 2*r - I;   // Left child,  reverse of lt = 2*r+1
+  var rt = lt  - 1;   // Right child, reverse of rt = 2*r+2
   if (lt>=i && fc(fm(x[lt], lt, x), fm(x[s], s, x)) < 0) s = lt;  // Left child is smaller?
   if (rt>=i && fc(fm(x[rt], rt, x), fm(x[s], s, x)) < 0) s = rt;  // Right child is smaller?
   if (s !== r) {     // Smallest is not root?
@@ -3283,6 +3389,36 @@ function reverseMinHeapify$<T, U=T>(x: T[], i: number, I: number, r: number, fc:
 }
 
 
+// Build a max-heap, where root node is the smallest and placed at the beginning.
+function buildMaxHeap$<T, U=T>(x: T[], i: number, I: number, fc: CompareFunction<T|U>, fm: MapFunction<T, T|U>, fs: SwapFunction<T>): void {
+  for (var r=i+Math.floor((I-i)/2)-1; r>=i; --r)
+    maxHeapify$(x, i, I, r, fc, fm, fs);
+}
+
+
+/**
+ * Max-heapify values, such that root node is the largest and placed at the beginning.
+ * @param x an array (updated!)
+ * @param i start index
+ * @param I end index (exclusive)
+ * @param r root index
+ * @param fc compare function (a, b)
+ * @param fm map function (v, i, x)
+ * @param fs swap function (x, i, j)
+ */
+function maxHeapify$<T, U=T>(x: T[], i: number, I: number, r: number, fc: CompareFunction<T|U>, fm: MapFunction<T, T|U>, fs: SwapFunction<T>): void {
+  var s  = r;         // Index of largest value
+  var lt = 2*r - i + 1;  // Left child,  like lt = 2*r+1
+  var rt = lt  + 1;      // Right child, like rt = 2*r+2
+  if (lt<I && fc(fm(x[lt], lt, x), fm(x[s], s, x)) > 0) s = lt;  // Left child  is larger?
+  if (rt<I && fc(fm(x[rt], rt, x), fm(x[s], s, x)) > 0) s = rt;  // Right child is larger?
+  if (s !== r) {     // Largest is not root?
+    fs(x, s, r);     // Swap root with largest
+    maxHeapify$(x, i, I, s, fc, fm, fs);  // Rebuild heap
+  }
+}
+
+
 /**
  * Partially arrange values in order!
  * @param x an array (updated!)

tests/index.test.ts

@@ -76,6 +76,7 @@ import {
   searchValue,
   searchValueRight,
   searchValueAll,
+  searchMinimumValues,
   searchInfix,
   searchInfixRight,
   searchInfixAll,
@@ -983,6 +984,13 @@ test("searchValueAll", () => {
 });
 
 
+test("searchMinimumValues", () => {
+  var x = [2, 5, 3, 1, 4];
+  var a = searchMinimumValues(x, 3);
+  expect(a).toStrictEqual([3, 0, 2]);
+});
+
+
 test("searchInfix", () => {
   var x = [1, 2, 3, 4];
   var y = [2, 3];