/**
 * Represents a segment tree for range queries.
 */
export declare class SegmentTree {
    private tree;
    private n;
    constructor(data: number[]);
    private build;
    /**
     * Updates a value in the segment tree.
     * @param {number} index - The index to update.
     * @param {number} value - The new value.
     */
    update(index: number, value: number): void;
    /**
     * Queries the sum in a range [left, right).
     * @param {number} left - The left index (inclusive).
     * @param {number} right - The right index (exclusive).
     * @returns {number} The sum in the range.
     */
    query(left: number, right: number): number;
}