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bool isShorter(const string &s1, const string &s2) { return s1.size() < s2.size(); }
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struct string // belongs to the type category literal type { constexpr explicit string( int v = 0 ) : value(v) {} constexpr int size() const { return value ; } // size() is constexpr const int value ; }; constexpr bool isShorter( const string& s1, const string& s2 ) { return s1.size() < s2.size(); }