[Leetcode][Javascript] 36. Valid Sudoku

1. 1개의 Set사용

/**
 * @param {character[][]} board
 * @return {boolean}
 */
var isValidSudoku = function(board) {
    let set= new Set();
    for (let i=0; i<board.length; i++){
        for(let j=0; j<board.length; j++){
            if(board[i][j]==='.') continue;
            else{
                let subsquare= (3*Math.floor(i/3) +Math.floor(j/3))
                const row=`${i}th row has ${board[i][j]}`
                const col=`${j}th column has ${board[i][j]}`
                const sub=`${subsquare}th square has ${board[i][j]}`
                if(set.has(row)||set.has(col)||set.has(sub)){
                   return false;
                   }
                else{
                set.add(row)
                set.add(col)
                set.add(sub)
                }
            }
        }
    }
    return true
};