Problem 595. Reduce - Map-Reduce

Created by Muthu Annamalai

Write reduce function, that takes arguments and constantly folds results into next call argument, finally returning a value; i.e. for a binary operator Fb,

     reduce(Fb,{a,b,c},start_val) = F(F(F(start_val,a),b),c)

Same can be done for a n-ary operators.

Eg. reduce(@strcat,{'foo','bar','baz','bat'},' ') = reduce(@plus,{1,2,3,4},0) = 10 reduce(@max,{1,2,3,4},{5,6,7,8},5) = 8

Remember, we use cell arrays for passing arguments, not matrices!

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6 solvers submitted 22 solutions (3.67 solutions/solver).

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3 Comments

@bmtran on 17 Apr 2012

could you separate your asserts into multiple cells so you can see which test case is failing?

@bmtran on 17 Apr 2012

also, how do you define the n-ary behavior since max only takes up to 2 non-empty arguments?

Muthu Annamalai on 17 Apr 2012

I mean, n-ary operators are also supported, but I use max as a binary op.

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Solution 77927

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Freddy on 17 Apr 2012

Can't exactly understand why this is shorter than @bmtran's version.

Problem 595. Reduce - Map-Reduce

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6 solvers submitted 22 solutions (3.67 solutions/solver).

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