This program illustrates the use of the STL search_n() algorithm
(extended version) to find instances of a consecutive sequence of
matching values in a vector of integers, where values match if and
only if they have the same digit sum.
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Here are the contents of the vector:
17 27 63 54 45 71 28 81 90 18 10 9 11
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The first instance of three consecutive integers
with a digit sum of 9 starts at location 2.
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The next instance of three consecutive integers
with a digit sum of 9 starts at location 3.
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The next instance of three consecutive integers
with a digit sum of 9 starts at location 8.
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No further instance of three consecutive integers
with a digit sum of 9 was found in the vector.
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