leetcode-73 矩阵置零

/**
 * @param {number[][]} matrix
 * @return {void} Do not return anything, modify matrix in-place instead.
 */
var setZeroes = function (matrix) {
  // 行
  const row = matrix.length;
  const col = matrix[0].length;
  const zeroRow = Array(row).fill(false);
  const zeroCol = Array(col).fill(false);
  for (let i = 0; i < row; ++i) {
    for (let j = 0; j < col; ++j) {
      if (matrix[i][j] === 0) {
        zeroRow[i] = true;
        zeroCol[j] = true;
      }
    }
  }
  for (let i = 0; i < row; ++i) {
    if (!zeroRow[i]) continue;
    for (let j = 0; j < col; ++j) {
      matrix[i][j] = 0;
    }
  }
  for (let i = 0; i < col; ++i) {
    if (!zeroCol[i]) continue;
    for (let j = 0; j < row; ++j) {
      matrix[j][i] = 0;
    }
  }
  return matrix;
};

/**
 * @param {number[][]} matrix
 * @return {void} Do not return anything, modify matrix in-place instead.
 */
var setZeroes = function (matrix) {
  const rowLen = matrix.length;
  const colLen = matrix[0].length;
  let firstRowZero = false,
    firstColZero = false;
  for (let i = 0; i < rowLen; i++) {
    if (matrix[i][0] === 0) {
      firstColZero = true;
    }
  }
  for (let i = 0; i < colLen; i++) {
    if (matrix[0][i] === 0) {
      firstRowZero = true;
    }
  }
  for (let i = 1; i < rowLen; i++) {
    for (let j = 1; j < colLen; j++) {
      if (matrix[i][j] === 0) {
        matrix[i][0] = 0;
        matrix[0][j] = 0;
      }
    }
  }
  for (let i = 1; i < rowLen; i++) {
    for (let j = 1; j < colLen; j++) {
      if (matrix[i][0] === 0 || matrix[0][j] === 0) {
        matrix[i][j] = 0;
      }
    }
  }
  // 处理首行、首列
  if (firstRowZero) {
    for (let i = 0; i < colLen; i++) {
      matrix[0][i] = 0;
    }
  }
  if (firstColZero) {
    for (let i = 0; i < rowLen; i++) {
      matrix[i][0] = 0;
    }
  }
  return matrix;
};