Summation of Primes
January 05, 2020 • ☕️ 1 min read
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
Find the sum of all the primes below two million.
const solutionTen = () => {
const primesLimitBools = (value: number) => {
let primes: boolean[] = [];
for (let index = 2; index < value; index++) {
primes[index] = true;
}
const limit = Math.sqrt(value);
for (let outer = 2; outer < limit; outer++) {
if (primes[outer] === true) {
for (let inner = outer * outer; inner < value; inner += outer) {
primes[inner] = false;
}
}
}
return primes;
};
const upperLimit = 2000000;
return primesLimitBools(upperLimit).reduce(
(a, b, i) => (b === true ? a + i : a + 0),
0
);
};