const searchMatrix = function (matrix, target) {
  if (matrix.length === 0) {
    return false;
  }
  let row = matrix.length-1,
    col = 0;
  while (row >= 0 && col < matrix[0].length) {
    if (matrix[row][col] === target) {
      return true;
    } else if (matrix[row][col] > target) {
      --row;
    } else {
      ++col
    }
  }
  return false;
};