找到最大的数字 [英] finding largest numbers
问题描述
我假设1000个数字在一个文件中。我必须在没有排序的情况下找出其中5个b $ b最大的数字。你能给我一个
有效的想法吗？我的想法是将这些数字放入
二叉树并找到最大的数字。我们还能怎样做呢？
问候
Hi,
I have, suppose 1000 numbers, in a file. I have to find out 5
largest numbers among them without sorting. Can you please give me an
efficient idea to do this? My idea is to put those numbers into a
binary tree and to find the largest numbers. How else can we do it?
Regards
推荐答案
qsort& bsearch< stdlib.h中>也许更好。
ramu写道：
qsort & bsearch<stdlib.h> perhaps better.
ramu wrote:
我假设有1000个数字，在一个文件中。我必须找出其中5个最大的数字而不进行排序。你能给我一个有效的想法吗？我的想法是将这些数字放入
二叉树中并找到最大的数字。我们还能做什么呢？
问候
Hi,
I have, suppose 1000 numbers, in a file. I have to find out 5
largest numbers among them without sorting. Can you please give me an
efficient idea to do this? My idea is to put those numbers into a
binary tree and to find the largest numbers. How else can we do it?
Regards
ph ***** @ gmail.com 说：
ramu写道：
<我想，假设1000个数字，在一个文件中。我必须找出其中5个最大的数字而不进行排序。你能给我一个有效的想法吗？我的想法是将这些数字放入
二叉树中并找到最大的数字。我们还能做什么呢？
Hi,
I have, suppose 1000 numbers, in a file. I have to find out 5
largest numbers among them without sorting. Can you please give me an
efficient idea to do this? My idea is to put those numbers into a
binary tree and to find the largest numbers. How else can we do it?
qsort& bsearch< stdlib.h中>也许更好。
qsort & bsearch<stdlib.h> perhaps better.
没有排序的音节是什么你在挣扎吗？
-
Richard Heathfield
Usenet是一个奇怪的地方 - dmr 29/7/1999
http://www.cpax.org.uk
电子邮件：rjh在上面的域名（但显然放弃了www）
Which syllable of "without sorting" were you struggling with?
--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)
ramu说：
ramu said:
假设1000个数字在一个文件中。我必须找出其中5个最大的数字而不进行排序。你能给我一个有效的想法吗？我的想法是将这些数字放入
二叉树中并找到最大的数字。我们还能做什么呢？
Hi,
I have, suppose 1000 numbers, in a file. I have to find out 5
largest numbers among them without sorting. Can you please give me an
efficient idea to do this? My idea is to put those numbers into a
binary tree and to find the largest numbers. How else can we do it?
二叉树基本上是一种排序技术，你说你是
不允许要做。
只需设置一个包含五个数字的数组m，并将它们全部设置为INT_MIN。
然后执行以下操作：
count = 0;
while（successful_got_next_number_in_file_into_n）
{
++ count;
c = 0;
for（j = 0; c == 0&& j< 5; j ++）
{
if（n> m [j]）
{
m [j] = n;
c = 1;
}
}
}
if（count< 5）
{
你仍然会在n中有一些INT_MIN条目，在报告程序结果时你应该忽略
。
}
如果你被允许保持m分类，有一种方法可以进一步减少
比较的数量，但我的回答是假设你不允许这样做
任何排序。
-
Richard Heathfield
Usenet是一个奇怪的地方 - dmr 29/7/1999
http://www.cpax.org.uk
电子邮件：rjh在上面的域名（但显然放弃了www）
A binary tree would basically be a sorting technique, which you say you''re
not allowed to do.
Just set up an array m of five numbers, and set them all to INT_MIN.
Then do something like this:
count = 0;
while(successfully_got_next_number_in_file_into_n)
{
++count;
c = 0;
for(j = 0; c == 0 && j < 5; j++)
{
if(n > m[j])
{
m[j] = n;
c = 1;
}
}
}
if(count < 5)
{
you will still have some INT_MIN entries in n, which you should disregard
when reporting the results of the program.
}
If you are allowed to keep m sorted, there is a way to reduce the number of
comparisons still further, but my answer assumes you are not allowed to do
any sorting at all.
--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)
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