<?phpfunction GetNumberOfK($data, $k){  if(count($data)==0){    return 0;  }  $index = 0;  $low = 0;  $high = count($data)-1;  $middle = 0;  //二分查找找到k的index  while($low<=$high){    $middle = ($high+$low)>>1;    if($data[$middle]==$k){      $index = $middle;      break;    }    else if($data[$middle]>$k) {      $high = $middle -1;    }else{      $low = $middle+1;    }    $index = -1;  }  // console.log(index);  // 如果沒找到  if($index==-1){    return 0;  }  //找到了 分別往左右查找邊界  $start = $index;  $end = $index;  $count = 0;  while($data[$start]==$k){    $count++;    $start--;  }  while($data[$end]==$k){    $count++;    $end++;  }  return $count-1;}