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<b>Data Structures and Algorithms 
with Object-Oriented Design Patterns in C++</b><br>
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<H1><A NAME="SECTION0015100000000000000000">Brute-Force and Greedy Algorithms</A></H1>
<A NAME="secalgsgreedy">&#160;</A>
<P>
In this section we consider two closely related algorithm types--brute-force and greedy.
<em>Brute-force algorithms</em><A NAME=32296>&#160;</A>
are distinguished not by their structure or form,
but by the way in which the problem to be solved is approached.
A brute-force algorithm solves a problem in the most simple,
direct or obvious way.
As a result, such an algorithm can end up doing far more work
to solve a given problem
than a more clever or sophisticated algorithm might do.
On the other hand,
a brute-force algorithm is often easier to implement
than a more sophisticated one and,
because of this simplicity,
sometimes it can be more efficient.
<P>
Often a problem can be viewed as a sequence of decisions to be made.
For example, consider the problem of finding the best way
to place electronic components on a circuit board.
To solve this problem we must decide
where on the board to place each component.
Typically, a brute-force algorithm solves such a problem
by exhaustively enumerating all the possibilities.
I.e., for every decision we consider each possible outcome.
<P>
A greedy algorithm is one that makes the sequence of decisions (in some order)
such that once a given decision has been made,
that decision is never reconsidered.
For example,
if we use a greedy algorithm to place the components on the circuit board,
once a component has been assigned a position it is never again moved.
Greedy algorithms can run significantly faster than brute force ones.
Unfortunately, it is not always the case that a greedy strategy
leads to the correct solution.
<P>
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<UL> 
<LI> <A NAME="tex2html7373" HREF="page442.html#SECTION0015110000000000000000" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page442.html#SECTION0015110000000000000000">Example-Counting Change</A>
<LI> <A NAME="tex2html7374" HREF="page445.html#SECTION0015120000000000000000" tppabs="http://dictator.uwaterloo.ca/Bruno.Preiss/books/opus4/html/page445.html#SECTION0015120000000000000000">Example-0/1 Knapsack Problem</A>
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