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// This module is browser compatible.
/** * Yields `r` length `Arrays` from the input `iterable`. Order of selection is * important and elements are chosen with replacement. * * ```ts * import { assertEquals } from "https://deno.land/std/testing/asserts.ts"; * import { permutationsWithReplacement } from "https://deno.land/x/combinatorics/mod.ts"; * * const sequences = [...permutationsWithReplacement([1, 2, 3, 4], 2)]; * * assertEquals(sequences, [ *   [1, 1], [1, 2], [1, 3], [1, 4], *   [2, 1], [2, 2], [2, 3], [2, 4], *   [3, 1], [3, 2], [3, 3], [3, 4], *   [4, 1], [4, 2], [4, 3], [4, 4], * ]); * ``` */export function* permutationsWithReplacement<T>(  iterable: Iterable<T>,  r: number,): Generator<T[]> {  if (!Number.isInteger(r) || r < 0) {    throw RangeError("r must be a non-negative integer");  }  const pool = [...iterable];  const n = pool.length;  if (r === 0) {    yield [];    return;  }  if (n === 0 && r > 0) {    return;  }  const indices = new Uint32Array(r);  yield Array(r).fill(pool[0]);  while (true) {    let i: number;    loop: {      for (i = r - 1; i >= 0; i--) {        if (indices[i] === n - 1) {          continue;        }        const result: T[] = Array(r);        for (let j = 0; j < i; j++) {          result[j] = pool[indices[j]];        }        const index = indices[i] += 1;        result[i] = pool[index];        for (let j = i + 1; j < r; j++) {          indices[j] = 0;          result[j] = pool[0];        }        yield result;        break loop;      }      return;    }  }}