// 입력
solution([[0,0,0,0,0],[0,0,1,0,3],[0,2,5,0,1],[4,2,4,4,2],[3,5,1,3,1]], [1,5,3,5,1,2,1,4])

// 출력
[2] // 4

// 내가 푼 답
const solution = (board, moves) => {
    let answer = 0;
    let arr = [];
    
    for(let i=0; i<moves.length; i++){
        if (board[moves[i]-1][board[moves[i]-1].length-1] !== 0) {
            arr.push(board[moves[i]-1].pop());
            if (arr.length > 1) {
                if(arr[arr.length-2] === arr[arr.length-1]) {
                    arr.splice(arr.length-2);
                    answer += 2;
                }
            }
        }
    }
   
    return answer;
}