ultra-mega-enumerator/dist/enumerations/WordPermutationEnumeration.js

Ultra Mega Enumerator is a lightweight library designed to enumerate various combinatorial objects.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.WordPermutationEnumeration = void 0;
const AbstractEnumeration_1 = require("./AbstractEnumeration");
const Combination_1 = require("./../objects/Combination"); // Assuming the Combination class is defined in Combination.ts
const MixedRadixEnumeration_1 = require("./MixedRadixEnumeration"); // Assuming the MixedRadixEnumeration class is defined in MixedRadixEnumeration.ts';
class WordPermutationEnumeration extends AbstractEnumeration_1.AbstractEnumeration {
    /**
     * For example, to enumerate the permutations of MISSISSIPPI,
     *
     * rk would be {1,4,4,2} because it has 1 M, 4 Is, 4 Ss, and 2 Ps.
     *
     * In the enumerated arrays, the 0s represent the M, the 1s the I,
     * the 2s the S and the 3 the Ps.
     *
     * @param rk Integer[]
     */
    constructor(rk) {
        super();
        if (rk == null) {
            throw new Error("null array");
        }
        const k = rk.length;
        this.n = 0;
        this.nonzeroIndices = [];
        for (let i = 0; i < k; i++) {
            if (rk[i] < 0) {
                throw new Error("null or negative element");
            }
            this.n += rk[i];
            if (rk[i] !== 0) {
                this.nonzeroIndices.push(i);
            }
        }
        let c = 0;
        const nzsz = this.nonzeroIndices.length;
        this.combis = new Array(nzsz);
        const sizes = new Array(nzsz);
        for (let i = 0; i < nzsz; i++) {
            const nz = this.nonzeroIndices[i];
            c += rk[nz];
            this.combis[i] = Combination_1.Combination.generateAll(c, rk[nz]);
            sizes[i] = this.combis[i].length;
        }
        this.it = new MixedRadixEnumeration_1.MixedRadixEnumeration(sizes);
    }
    hasMoreElements() {
        return this.it.hasMoreElements();
    }
    nextElement() {
        if (!this.hasMoreElements()) {
            throw new Error("No such element");
        }
        const mr = this.it.nextElement();
        const pos = Array.from({ length: this.n }, (_, i) => i);
        const x = new Array(this.n).fill(0);
        for (let i = mr.length - 1; i >= 0; i--) {
            const p = this.combis[i][mr[i]];
            for (let j = p.size() - 1; j >= 0; j--) {
                if (p.get(j)) {
                    x[pos[j]] = this.nonzeroIndices[i];
                    pos.splice(j, 1); // Remove the position at index j
                }
            }
        }
        return x.reverse();
    }
}
exports.WordPermutationEnumeration = WordPermutationEnumeration;
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