https://programmers.co.kr/learn/courses/30/lessons/70128
function solution(a, b) {
var sum = 0;
for(let i = 0; i < a.length; i++) {
sum += a[i] * b[i];
}
return sum;
}
//다른 사람 풀이
function solution(a, b) {
return a.reduce((acc, _, i) => acc += a[i] * b[i], 0);
}