malwoden/dist/lib/struct/priority-queue-array.js

   

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.ArrayPriorityQueue = void 0;
/**
 * ArrayPriorityQueue allows for push/pop based on an attribute
 * of the inserted objects. The array based implementation
 * underneath has theoretic O(c) insert time, and O(n)
 * peek/pop time.
 *
 * Though this is slower in many cases than the heap based implementation,
 * it preserves the order better and can result in more 'normal' paths
 * when used with pathfinding.
 */
var ArrayPriorityQueue = /** @class */ (function () {
    /**
     * @param priorityFunc - A function that takes the a value that
     * has previously been inserted, and returns a priority.
     *
     * A lower score is higher priority.
     *
     * Ex. (monster) => monster.speed
     */
    function ArrayPriorityQueue(priorityFunc) {
        this.data = [];
        this.priorityFunc = priorityFunc;
    }
    /**
     * Insert data into the queue
     * @param data - The data to insert
     */
    ArrayPriorityQueue.prototype.insert = function (data) {
        var score = this.priorityFunc(data);
        this.data.push([score, data]);
    };
    /**
     * Get the item with the lowest priority score,
     * removing it from the queue.
     * @returns - The lowest priority item
     */
    ArrayPriorityQueue.prototype.pop = function () {
        if (this.data.length === 0)
            return undefined;
        var min = Infinity;
        var minIndex = -1;
        this.data.forEach(function (_a, index) {
            var val = _a[0], d = _a[1];
            if (val < min) {
                min = val;
                minIndex = index;
            }
        });
        var popped = this.data.splice(minIndex, 1);
        return popped[0][1];
    };
    /**
     * Get the item with the lowest priotity score,
     * WITHOUT removing it.
     * @returns - The lowest priority item
     */
    ArrayPriorityQueue.prototype.peek = function () {
        if (this.data.length === 0)
            return undefined;
        var min = Infinity;
        var minIndex = -1;
        this.data.forEach(function (_a, index) {
            var val = _a[0], d = _a[1];
            if (val < min) {
                min = val;
                minIndex = index;
            }
        });
        return this.data[minIndex][1];
    };
    /**
     * Returns the number of items in the queue.
     * @returns - Number of items in the queue.
     */
    ArrayPriorityQueue.prototype.size = function () {
        return this.data.length;
    };
    return ArrayPriorityQueue;
}());
exports.ArrayPriorityQueue = ArrayPriorityQueue;
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