📄 stable_sort.html
字号:
<HTML><!-- -- Copyright (c) 1996-1999 -- Silicon Graphics Computer Systems, Inc. -- -- Permission to use, copy, modify, distribute and sell this software -- and its documentation for any purpose is hereby granted without fee, -- provided that the above copyright notice appears in all copies and -- that both that copyright notice and this permission notice appear -- in supporting documentation. Silicon Graphics makes no -- representations about the suitability of this software for any -- purpose. It is provided "as is" without express or implied warranty. -- -- Copyright (c) 1994 -- Hewlett-Packard Company -- -- Permission to use, copy, modify, distribute and sell this software -- and its documentation for any purpose is hereby granted without fee, -- provided that the above copyright notice appears in all copies and -- that both that copyright notice and this permission notice appear -- in supporting documentation. Hewlett-Packard Company makes no -- representations about the suitability of this software for any -- purpose. It is provided "as is" without express or implied warranty. -- --><Head><Title>stable_sort</Title><!-- Generated by htmldoc --></HEAD><BODY TEXT="#000000" LINK="#006600" ALINK="#003300" VLINK="#7C7F87" BGCOLOR="#FFFFFF"><A HREF="/"><IMG SRC="/images/common/sgilogo_small.gif" ALT="SGI Logo" WIDTH="80" HEIGHT="72" BORDER="0"></A><P><!--end header--><BR Clear><H1>stable_sort</H1><Table CellPadding=0 CellSpacing=0 width=100%><TR><TD Align=left><Img src = "algorithms.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD><TD Align=right><Img src = "function.gif" Alt="" WIDTH = "194" HEIGHT = "38" ></TD></TR><TR><TD Align=left VAlign=top><b>Category</b>: algorithms</TD><TD Align=right VAlign=top><b>Component type</b>: function</TD></TR></Table><h3>Prototype</h3><tt>Stable_sort</tt> is an overloaded name; there are actually two <tt>stable_sort</tt>functions.<pre>template <class <A href="RandomAccessIterator.html">RandomAccessIterator</A>>void stable_sort(RandomAccessIterator first, RandomAccessIterator last);template <class <A href="RandomAccessIterator.html">RandomAccessIterator</A>, class <A href="StrictWeakOrdering.html">StrictWeakOrdering</A>>void stable_sort(RandomAccessIterator first, RandomAccessIterator last, StrictWeakOrdering comp);</pre> <h3>Description</h3><tt>Stable_sort</tt> is much like <tt><A href="sort.html">sort</A></tt>: it sorts the elements in<tt>[first, last)</tt> into ascending order, meaning that if <tt>i</tt> and <tt>j</tt> areany two valid iterators in <tt>[first, last)</tt> such that <tt>i</tt> precedes <tt>j</tt>,then <tt>*j</tt> is not less than <tt>*i</tt>. <tt>Stable_sort</tt> differs from<tt><A href="sort.html">sort</A></tt> in two ways. First, <tt>stable_sort</tt> uses an algorithm thathas different run-time complexity than <tt><A href="sort.html">sort</A></tt>. Second, as thename suggests, <tt>stable_sort</tt> is stable: it preserves the relativeordering of equivalent elements. That is, if <tt>x</tt> and <tt>y</tt> are elementsin <tt>[first, last)</tt> such that <tt>x</tt> precedes <tt>y</tt>, and if the twoelements are equivalent (neither <tt>x < y</tt> nor <tt>y < x</tt>)then a postcondition of <tt>stable_sort</tt> is that <tt>x</tt> still precedes <tt>y</tt>.<A href="#1">[1]</A><P>The two versions of <tt>stable_sort</tt> differ in how they define whether oneelement is less than another. The first version comparesobjects using <tt>operator<</tt>, and the second compares objects usinga <A href="functors.html">function object</A> <tt>comp</tt>.<h3>Definition</h3>Defined in the standard header <A href="algorithm">algorithm</A>, and in the nonstandardbackward-compatibility header <A href="algo.h">algo.h</A>.<h3>Requirements on types</h3>For the first version, the one that takes two arguments:<UL><LI><tt>RandomAccessIterator</tt> is a model of <A href="RandomAccessIterator.html">Random Access Iterator</A>.<LI><tt>RandomAccessIterator</tt> is mutable.<LI><tt>RandomAccessIterator</tt>'s value type is <A href="LessThanComparable.html">LessThan Comparable</A>.<LI>The ordering relation on <tt>RandomAccessIterator</tt>'s value type is a <i>strict weak ordering</i>, as defined in the <A href="LessThanComparable.html">LessThan Comparable</A> requirements.</UL>For the second version, the one that takes three arguments:<UL><LI><tt>RandomAccessIterator</tt> is a model of <A href="RandomAccessIterator.html">Random Access Iterator</A>.<LI><tt>RandomAccessIterator</tt> is mutable.<LI><tt>StrictWeakOrdering</tt> is a model of <A href="StrictWeakOrdering.html">Strict Weak Ordering</A>.<LI><tt>RandomAccessIterator</tt>'s value type is convertible to <tt>StrictWeakOrdering</tt>'s argument type.</UL><h3>Preconditions</h3><UL><LI><tt>[first, last)</tt> is a valid range.</UL><h3>Complexity</h3><tt>Stable_sort</tt> is an <i>adaptive</i> algorithm: it attempts toallocate a temporary memory buffer, and its run-time complexity dependson how much memory is available. Worst-case behavior (if no auxiliary memoryis available) is <tt>N (log N)^2</tt> comparisons, where <tt>N</tt> is <tt>last -first</tt>, and best case (if a large enough auxiliary memory buffer is available)is <tt>N (log N)</tt>. <A href="#2">[2]</A><h3>Example</h3>Sort a sequence of characters, ignoring their case. Note that therelative order of characters that differ only by case is preserved.<pre>inline bool lt_nocase(char c1, char c2) { return tolower(c1) < tolower(c2); }int main(){ char A[] = "fdBeACFDbEac"; const int N = sizeof(A) - 1; stable_sort(A, A+N, lt_nocase); printf("%s\n", A); // The printed result is ""AaBbCcdDeEfF".}</pre><h3>Notes</h3><P><A name="1">[1]</A>Note that two elements may be equivalent without being equal.One standard example is sorting a sequence of names by last name: iftwo people have the same last name but different first names, thenthey are equivalent but not equal. This is why <tt>stable_sort</tt> issometimes useful: if you are sorting a sequence of records that haveseveral different fields, then you may want to sort it by one fieldwithout completely destroying the ordering that you previously obtained from sorting it by a different field. You might, forexample, sort by first name and then do a stable sort by last name.<P><A name="2">[2]</A><tt>Stable_sort</tt> uses the <i>merge sort</i> algorithm; see section5.2.4 of Knuth. (D. E. Knuth, <i>The Art of ComputerProgramming. Volume 3: Sorting and Searching</i>. Addison-Wesley, 1975.)<h3>See also</h3><tt><A href="sort.html">sort</A></tt>,<tt><A href="partial_sort.html">partial_sort</A></tt>,<tt><A href="partial_sort_copy.html">partial_sort_copy</A></tt>,<tt><A href="binary_search.html">binary_search</A></tt>,<tt><A href="lower_bound.html">lower_bound</A></tt>,<tt><A href="upper_bound.html">upper_bound</A></tt>,<tt><A href="less.html">less</A><T></tt>,<A href="StrictWeakOrdering.html">StrictWeakOrdering</A>,<A href="LessThanComparable.html">LessThan Comparable</A><!-- start footer --><!-- Footer Begins --><STYLE TYPE="text/css"><!--TD.footer, TD.footer A{ font-family: Arial, helvetica, sans-serif; font-size: 8pt;}A.home {font-family: Arial, helvetica, sans-serif;}--></STYLE><P><A CLASS="home" HREF="index.html">STL Home</A><P><TABLE WIDTH="600" CELLPADDING="0" CELLPADDING="0" BORDER="0"> <TR> <TD ALIGN="RIGHT" CLASS="footer"><A HREF="/company_info/terms.html" TARGET="_top">terms of use</A> | <A HREF="/company_info/privacy.html" TARGET="_top">privacy policy</A></TD> <TD ALIGN="CENTER" CLASS="footer"> | </TD> <TD ALIGN="LEFT" CLASS="footer"><A HREF="/cgi-bin/feedback/" TARGET="_top">contact us</A></TD> </TR><TR> <TD ALIGN="RIGHT" CLASS="footer">Copyright © 1993-2003 Silicon Graphics, Inc. All rights reserved.</TD> <TD ALIGN="CENTER" CLASS="footer"> | </TD> <TD ALIGN="LEFT" CLASS="footer"><A HREF="/company_info/trademarks/" TARGET="_top">Trademark Information</A></TD> </TR></TABLE><!-- Footer Ends --><!-- end footer --><P></BODY></HTML> ⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -