View Compilation Error

0_0_32513872_0.cpp: In function 'int main()':
0_0_32513872_0.cpp:72:23: error: no match for 'operator!' (operand type is 'std::string {aka std::basic_string<char>}')
         if (SPFA() || !dist[s] == INF)
                       ^
0_0_32513872_0.cpp:72:23: note: candidate is:
0_0_32513872_0.cpp:72:23: note: operator!(bool) <built-in>
0_0_32513872_0.cpp:72:23: note:   no known conversion for argument 1 from 'std::string {aka std::basic_string<char>}' to 'bool'