solution.js

/**
 * @param {number[]} nums
 * @param {number} n
 * @param {number} left
 * @param {number} right
 * @return {number}
 */
var rangeSum = function (nums, n, left, right) {
    const sums = [];
    let sum = 0;
    for (let i = 0; i < nums.length; i++) {
        sum += nums[i];
        sums.push(sum);
    }

    const count = nums.length - 1;
    for (let i = 1; i < nums.length; i++) {
        const count = nums.length - i;
        const start = sums.length - count;
        const end = sums.length;
        const remove = nums[i - 1];
        for (let j = start; j < end; j++) {
            sums.push(sums[j] - remove);
        }
    }

    sums.sort((a, b) => a - b);
    left--;

    let result = 0;
    const mod = 10 ** 9 + 7;
    for (let i = left; i < right; i++) {
        result = (result + sums[i]) % mod;
    }
    return result;
};