풀이 1
function solution(a, b) { let answer = 0 for (let i=0 ; i<a.length; i++){ answer += a[i]*b[i] } return answer
풀이 2
function solution(a, b) { return a.map( (v,i) => a[i]*b[i] ).reduce( (acc,crr ) => acc+crr,0) }
풀이 3
function solution(a, b) { return a.reduce( (acc, crr , i) => acc += a[i] * b[i] , 0) } }