LeetCode/go/range-sum-of-sorted-subarray-sums.go

package main

import (
	"cmp"

	pq "github.com/emirpasic/gods/v2/queues/priorityqueue"
)

const MOD int = 1_000_000_007

type Sum struct {
	index int
	sum   int
}

func cmpSum(a, b Sum) int {
	return cmp.Compare(a.sum, b.sum)
}

func rangeSum(nums []int, n int, left int, right int) int {
	q := pq.NewWith[Sum](cmpSum)

	for i, num := range nums {
		q.Enqueue(Sum{index: i, sum: num})
	}

	total := 0
	for i := 1; i <= right; i++ {
		s, _ := q.Dequeue()

		if i >= left {
			total = (total + s.sum) % MOD
		}

		if s.index < n-1 {
			s.index++
			s.sum += nums[s.index]
			q.Enqueue(s)
		}
	}

	return total
}