js-combinatorics - npm Package Compare versions

Comparing version 1.3.0 to 1.4.0

combinatorics.d.ts

@@ -14,3 +14,3 @@ /**
  */
-export declare const version = "1.3.0";
+export declare const version = "1.4.0";
 /**
@@ -53,2 +53,8 @@ * BigInt Workaround
 /**
+ * returns the combinadics representation of `m` for `n C k`.
+ *
+ * @link https://en.wikipedia.org/wiki/Combinatorial_number_system
+ */
+export declare function combinadic(n: any, k: any, m: any): any[];
+/**
  * returns random integer `n` where `min` <= `n` < `max`:
@@ -111,3 +117,3 @@ *
 export declare class Permutation extends _CBase {
-    constructor(seed: any, size?: number);
+    constructor(seed: Iterable<any>, size?: number);
     nth(n: anyint, nocheck?: boolean): Optional<any[]>;
@@ -114,0 +120,0 @@ }

combinatorics.js

@@ -14,3 +14,3 @@ /**
  */
-export const version = '1.3.0';
+export const version = '1.4.0';
 const _BI = typeof BigInt == 'function' ? BigInt : Number;
@@ -76,4 +76,24 @@ /**
 /**
+ * returns the combinadics representation of `m` for `n C k`.
  *
+ * @link https://en.wikipedia.org/wiki/Combinatorial_number_system
  */
+export function combinadic(n, k, m) {
+    let digits = [];
+    let a = n;
+    let b = k;
+    let x = _BI(combination(n, k)) - _BI(1) - _BI(m);
+    for (let i = 0; i < k; i++) {
+        a--;
+        while (x < combination(a, b))
+            a--;
+        digits.push(n - 1 - a);
+        x -= _BI(combination(a, b));
+        b--;
+    }
+    return digits;
+}
+/**
+ *
+ */
 const _crypto = typeof crypto !== 'undefined' ? crypto : {};
@@ -194,3 +214,3 @@ const _randomBytes = typeof _crypto['randomBytes'] === 'function'
         this.size = 0 < size && size <= this.seed.length ? size : this.seed.length;
-        this.length = permutation(seed.length, this.size);
+        this.length = permutation(this.seed.length, this.size);
         Object.freeze(this);
@@ -220,6 +240,5 @@ }
         super();
-        const sseed = [...seed];
-        this.perm = new Permutation(sseed, size);
-        this.size = this.perm.size;
-        this.length = combination(sseed.length, this.size);
+        this.seed = [...seed];
+        this.size = 0 < size && size <= this.seed.length ? size : this.seed.length;
+        this.length = combination(this.seed.length, this.size);
         Object.freeze(this);
@@ -231,14 +250,4 @@ }
             return undefined;
-        function findIndex(n) {
-            const [one, two] = typeof n === 'bigint' ? [_BI(1), _BI(2)] : [1, 2];
-            if (n <= two)
-                return n;
-            let p = n - one;
-            let s = p & -p;
-            let r = p + s;
-            let t = r & -r;
-            let m = ((t / s) >> one) - one;
-            return r | m;
-        }
-        return this.perm.nth(findIndex(n), true);
+        return combinadic(this.seed.length, this.size, n)
+            .reduce((a, v) => a.concat(this.seed[v]), []);
     }
@@ -245,0 +254,0 @@ }

package.json

 {
   "name": "js-combinatorics",
-  "version": "1.3.0",
+  "version": "1.4.0",
   "description": "Simple combinatorics like power set, combination, and permutation in JavaScript",
@@ -5,0 +5,0 @@ "main": "combinatorics.js",

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31605

increased by1.36%

Lines of code

480

increased by3.23%

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