[Programmers] 코딩테스트 입문 - 안전지대

https://school.programmers.co.kr/learn/courses/30/lessons/120866

프로그래머스

function solution(board) {
    const vector = [[1,0],[-1,0],[0,1],[0,-1], [-1,-1], [-1, 1], [1,1], [1, -1]];
    
    for(let i = 0 ; i < board.length ; i++) {
        for( let j = 0 ; j < board[0].length; j++) {
            if(board[i][j] === 1) {
                const vectors = [];
                vector.forEach(v => {
                    const x = v[0] + i;
                    const y = v[1] + j;
                    
                    if(x >= 0 && y >= 0 && x < board.length && y < board[0].length) {
                        vectors.push([x,y]);
                    }
                });
                
                vectors.forEach((v) => {
                    if(board[v[0]][v[1]] === 0) {
                        board[v[0]][v[1]] = -1;
                    }
                })
            }
        }
    }
    
    let answer = 0;
    board.forEach((bb) => {
        bb.forEach((b) => {
            if(b === 0) {
                answer++;
            }
        })
    })
    
    return answer;
}