Sum of Parts of An Array - JavaScript
There is no reason to compute the sum over and over. On a long array this will be very inefficient ( O(n²) ) and might explain your timeout errors. Compute the sum at the beginning and then subtract each element from it in a loop.
ls = [0, 1, 3, 6, 10]
function partsSums(ls) {
let sum = ls.reduce((sum, n) => sum + n, 0)
res = [sum]
for (let i = 1; i <= ls.length; i++){
sum -= ls[i-1]
res.push(sum )
}
return res
}
console.log(partsSums(ls))Another solution that passed all of the tests:
function partsSums(ls) {
let result = [0],
l = ls.length - 1;
for (let i = l; i >= 0; i--) {
result.push(ls[i] + result[ l - i]);
}
return result.reverse();
}
console.log(partsSums([]));
console.log(partsSums([0, 1, 3, 6, 10]));
console.log(partsSums([1, 2, 3, 4, 5, 6]));
console.log(partsSums([744125, 935, 407, 454, 430, 90, 144, 6710213, 889, 810, 2579358]));