Solution.js

const isValidSudoku = function (board) {
  let existed = new Set();
  for (let i = 0; i < 9; i++) {
    for (let j = 0; j < 9; j++) {
      let number = board[i][j];
      if (board[i][j] !== ".") {
        if (
          existed.has(number + " in row " + i) ||
          existed.has(number + " in column " + j) ||
          existed.has(
            number + "in block " + parseInt(i / 3) + "-" + parseInt(j / 3)
          )
        ) {
          return false;
        } else {
          existed.add(number + " in row " + i);
          existed.add(number + " in column " + j);
          existed.add(
            number + "in block " + parseInt(i / 3) + "-" + parseInt(j / 3)
          );
        }
      }
    }
  }
  return true;
};

/**
 * @param {character[][]} board
 * @return {boolean}
 */
const isValidSudoku2 = function (board) {
  function lineTest(arr) {
    for (let i = 0; i < 9; i++) {
      for (let j = 0; j < 9; j++) {
        for (let k = j + 1; k < 9; k++) {
          if (arr[i][j] === arr[i][k] && arr[i][j] !== ".") {
            return false;
          }
        }
      }
    }
    return true;
  }
  function columnTest(arr) {
    for (let i = 0; i < 9; i++) {
      for (let j = 0; j < 9; j++) {
        for (let k = j + 1; k < 9; k++) {
          if (arr[j][i] === arr[k][i] && arr[j][i] !== ".") {
            return false;
          }
        }
      }
    }
    return true;
  }
  function squareTest(arr) {
    let p = [
      [1, 1],
      [1, 4],
      [1, 7],
      [4, 1],
      [4, 4],
      [4, 7],
      [7, 1],
      [7, 4],
      [7, 7],
    ];

    for (let i = 0; i < p.length; i++) {
      let a = [];
      let x = p[i][0];
      let y = p[i][1];
      a.push(arr[x - 1][y - 1]);
      a.push(arr[x - 1][y]);
      a.push(arr[x - 1][y + 1]);
      a.push(arr[x][y - 1]);
      a.push(arr[x][y]);
      a.push(arr[x][y + 1]);
      a.push(arr[x + 1][y - 1]);
      a.push(arr[x + 1][y]);
      a.push(arr[x + 1][y + 1]);
      for (let j = 0; j < a.length; j++) {
        for (let k = j + 1; k < a.length; k++) {
          if (a[j] === a[k] && a[j] !== ".") {
            return false;
          }
        }
      }
    }
    return true;
  }
  return lineTest(board) && columnTest(board) && squareTest(board);
};