php 如何快速判断一个数字属于什么范围 ..?
需求是这样 ...
<code>if ( $foo > 0 && $foo 99 && $foo 211 && $foo 323 && $foo 381 && $foo 464 && $foo </code>
这样的规则有上千条 ... 于是满屏幕都是 $foo > __ && $foo
效率和美观都成问题 ...
临界点的数值近乎随机 ... 我想不到可以通过 $foo 推算 $bar 的公式 ...
目前的想法是把所有的规则二分掉 ... 这样可以提高效率 ... 但美观依然是问题 ...
如果封在一个函数里 ... 看上去似乎确实美观一些 ... 但效率反而不如这样 ...
有没有什么两者兼顾的比较完美的解决方案 ..?
追加 ... 自己写了一个借助数组排序的方案 ...
效率和自己实现函数差不多 ... 依然不如二分 ...
回复内容：
需求是这样 ...
<code>if ( $foo > 0 && $foo 99 && $foo 211 && $foo 323 && $foo 381 && $foo 464 && $foo </code>
这样的规则有上千条 ... 于是满屏幕都是 $foo > __ && $foo
效率和美观都成问题 ...
临界点的数值近乎随机 ... 我想不到可以通过 $foo 推算 $bar 的公式 ...
目前的想法是把所有的规则二分掉 ... 这样可以提高效率 ... 但美观依然是问题 ...
如果封在一个函数里 ... 看上去似乎确实美观一些 ... 但效率反而不如这样 ...
有没有什么两者兼顾的比较完美的解决方案 ..?
追加 ... 自己写了一个借助数组排序的方案 ...
效率和自己实现函数差不多 ... 依然不如二分 ...
假设你的范围是之间是连续的（其实不连续也很容易实现）、没有重合的（这个没问题吧），那么通过对范围的起始位置排序，就可以很容易地用二分来实现。
<code>$ranges = array(1, 100, 212, 324, 382, 465, 552); </code>
然后你要做的事情就是用二分查找在ranges里面找到一个a[i]满足a[i] 。
p.s. 吐槽一下你的范围，我看得有点精神分裂。
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