export declare class PriorityQueue {
    _arr: Array<{
        key: string;
        priority: number;
    }>;
    _keyIndices: {
        [key: string]: number;
    };
    constructor();
    size(): number;
    keys(): string[];
    has(key: string): boolean;
    priority(key: string): number;
    min(): string;
    add(key: string, priority: number): boolean;
    removeMin(): string;
    decrease(key: string, priority: number): void;
    _heapify(i: number): void;
    _decrease(index: number): void;
    _swap(i: number, j: number): void;
}