How to use STL binary search operations with pairs ? I also wish to use lower_bound function . Is it possible ?
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std::pair overloads the operator< thus any algorithm that uses ordering will work with pairs (assuming you've overloaded operator< for the pair members). The ordering is first by the first member and then by second if the first parts are equal. The lower_bound function that takes no predicate as argument uses the operator< for the comparison, thus it will work for pairs too.
Ivaylo Strandjev
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Can you give sample illustration on how to implement it (lower_bound particularly), i am still not clear with it :) – Maggi Iggam Apr 06 '15 at 14:04
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1If your question is how to overload the < operator, have a look [here](http://stackoverflow.com/q/4421706/812912) – Ivaylo Strandjev Apr 06 '15 at 14:06
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Hey i am not able to make it work , pair doesn't has iterators . Can you please provide a snippet on how to use lower_bound function on say pair
please? – Maggi Iggam Apr 06 '15 at 15:03 -
A lower_bound is defined on a collection not an object. Maybe I misunderstood your question - what exactly are you trying to do? – Ivaylo Strandjev Apr 06 '15 at 15:06
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I'm searching for pairs where (pair.first == foo) how do I state that as a val? – Jorge Barrios Oct 04 '17 at 00:17