47 lines
764 B
C++
47 lines
764 B
C++
/* Check cf5-opt.vim defs.
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VIM: let g:lcppflags="-std=c++11 -O2 -pthread"
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VIM: let g:wcppflags="/O2 /EHsc /DWIN32"
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*/
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#include <iostream>
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/*
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Even Fibonacci numbers
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Problem 2
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Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:
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1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
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By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.
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Solution:
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4613732
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*/
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int main ( void )
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{
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int x = 1;
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int y = 2;
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int z = x+y;
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int s = 0;
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while ( z < 4000000 )
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{
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s+= z;
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x = y;
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y = z;
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z = x+y;
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}
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if ( y%2 )
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{
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s -= y;
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if ( x%2 )
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s -= x;
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}
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s /= 2;
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s += 2;
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std::cout << s << std::endl;
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return 0;
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}
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