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来自「Data Structures And Algorithms With Obje」· HTML 代码 · 共 182 行 · 第 1/2 页
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</TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 0 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP>-- </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 0 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP>-- </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 0 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP>-- </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 0 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP>-- </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 0 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP>-- </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 0 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP>-- </TD></TR><TR><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>c</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 5 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>b</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 4 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>a</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 4 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>a</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 4 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>a</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 4 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>a</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 4 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>a</I> </TD></TR><TR><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>d</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 6 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>c</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 6 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP><I>c</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 6 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP><I>c</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 6 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP><I>c</I> </TD></TR><TR><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>e</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 8 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP><I>c</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 8 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP><I>c</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 8 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP><I>c</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 8 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP><I>c</I> </TD></TR><TR><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>f</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" > </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 11 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>d</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> 9 </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <I>e</I> </TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP> <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" ></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP>9</TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP></TD><TD VALIGN=BASELINE ALIGN=CENTER NOWRAP><I>e</I> </TD></TR></TBODY><CAPTION ALIGN=BOTTOM><STRONG>Table:</STRONG> Operation of Dijkstra's algorithm.</CAPTION></TABLE></P></DIV><P><P>Initially all the tentative distances are <IMG WIDTH=14 HEIGHT=7 ALIGN=BOTTOM ALT="tex2html_wrap_inline68397" SRC="img1875.gif" >,except for vertex <I>b</I> which has tentative distance zero.Therefore, vertex <I>b</I> is selected in the first pass.The mark <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > beside an entry in Table <A HREF="page565.html#tblgraphsdijkstra"><IMG ALIGN=BOTTOM ALT="gif" SRC="../icons/cross_ref_motif.gif"></A>indicates that the shortest path is <em>known</em> ( <IMG WIDTH=69 HEIGHT=22 ALIGN=MIDDLE ALT="tex2html_wrap_inline71767" SRC="img2364.gif" >).<P>Next we follow the edges emanating from vertex <I>b</I>, <IMG WIDTH=39 HEIGHT=11 ALIGN=BOTTOM ALT="tex2html_wrap_inline71771" SRC="img2365.gif" > and <IMG WIDTH=38 HEIGHT=11 ALIGN=BOTTOM ALT="tex2html_wrap_inline71773" SRC="img2366.gif" >,and update the distances accordingly.The new tentative distances for <I>a</I> becomes 3and the new tentative distance for <I>c</I> is 5.In both cases, the next-to-last vertex on the shortest path is vertex <I>b</I>.<P>In the second pass, vertex <I>a</I> is selected andits entry is marked with <IMG WIDTH=13 HEIGHT=26 ALIGN=MIDDLE ALT="tex2html_wrap_inline71639" SRC="img2362.gif" > indicating the shortest path is known.There is one edge emanating from <I>a</I>, <IMG WIDTH=41 HEIGHT=8 ALIGN=BOTTOM ALT="tex2html_wrap_inline71791" SRC="img2367.gif" >.The distance to <I>c</I> via <I>a</I> is 4.Since this is less than the tentative distance to <I>c</I>,vertex <I>c</I> is given the new tentative distance 4and its predecessor on the shortest-path is set to <I>a</I>.The algorithm continues in this fashionfor a total of <IMG WIDTH=11 HEIGHT=12 ALIGN=BOTTOM ALT="tex2html_wrap_inline70551" SRC="img2167.gif" > passesuntil all the shortest paths have been found.<P>The shortest-path information contained in the right-most columnof Table <A HREF="page565.html#tblgraphsdijkstra"><IMG ALIGN=BOTTOM ALT="gif" SRC="../icons/cross_ref_motif.gif"></A>can be represented in the form of a vertex-weighted graphas shown in Figure <A HREF="page565.html#figgraph13"><IMG ALIGN=BOTTOM ALT="gif" SRC="../icons/cross_ref_motif.gif"></A>.<P><P><A NAME="52051"> </A><A NAME="figgraph13"> </A> <IMG WIDTH=575 HEIGHT=186 ALIGN=BOTTOM ALT="figure51680" SRC="img2368.gif" ><BR><STRONG>Figure:</STRONG> The shortest-path graph for <IMG WIDTH=24 HEIGHT=23 ALIGN=MIDDLE ALT="tex2html_wrap_inline71499" SRC="img2337.gif" >.<BR><P><P>This graph contains the same set of vertices as the problem graph <IMG WIDTH=24 HEIGHT=23 ALIGN=MIDDLE ALT="tex2html_wrap_inline71499" SRC="img2337.gif" >.Each vertex <I>v</I> is labeled with the length <IMG WIDTH=14 HEIGHT=22 ALIGN=MIDDLE ALT="tex2html_wrap_inline71553" SRC="img2348.gif" >of the shortest path from <I>b</I> to <I>v</I>.Each vertex (except <I>b</I>) has a single emanating edgethat connects the vertex to the next-to-last vertex on the shortest-path.By following the edges in this graph from any vertex <I>v</I> to vertex <I>b</I>,we can construct the shortest path from <I>b</I> to <I>v</I> in reverse.<P><HR><A NAME="tex2html7656" 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