max-sum-of-two-ranges-in-array.js

function maxSumOfTwoRangesIn(arr) {
    const ranges = [[]];
    for (let i = 0; i < arr.length; i++) {
        const last = ranges.length - 1;
        for (let j = 0; j <= last; j++) {
            // ranges.push(ranges[j].concat(i))
            ranges.push([...ranges[j], i]);
        }
    }

    let maxRangesSum;

    for (let i = 0; i < ranges.length; i++) {
        for (let j = i + 1; j < ranges.length; j++) {
            if (ranges[j][0] > ranges[i].at(-1)) {
                const a = arr.slice(ranges[i][0], ranges[i].at(-1) + 1)
                const b = arr.slice(ranges[j][0], ranges[j].at(-1) + 1)
                let s = 0;
                for (let i = 0; i < Math.max(a.length, b.length); i++) {
                    s += (a[i] || 0) + (b[i] || 0)
                }
                if (!maxRangesSum || s > maxRangesSum) {
                    maxRangesSum = s
                }
            }
        }
    }

    return maxRangesSum
}


console.log(maxSumOfTwoRangesIn([-5,9,-5,10,20]))
console.log(maxSumOfTwoRangesIn([1,2,3,4,5,6]))
console.log(maxSumOfTwoRangesIn([-1,-2,-3,-4,-5,-6]))
console.log(maxSumOfTwoRangesIn([1000,-100,-200,2000,-400,500,-600]))
console.time('et')
console.log(maxSumOfTwoRangesIn([-500,1000,-100,-2000,500,500,500,-5000,2000,-100,-200,3000,-400,500,-600]))
console.timeEnd('et')