일곱 난쟁이

function solution(arr) {
    let answer = [];
    let sum = arr.reduce((a, b) => a + b, 0); 
    let garbage = sum - 100; 

    for(let i=0; i<arr.length; i++) {
        for(let j=1; j<arr.length-1; j++) {
            if(arr[i] + arr[j] === garbage) {
                answer = arr.filter(function(e) {
                    return (e !== arr[i]) && (e !== arr[j]);
                })
                break; 
            }
        }
    }
    return answer;
}

arr = [20, 7, 23, 19, 10, 15, 25, 8, 13];
console.log(solution(arr));