foo.cc: In function 'bool Spfa(int)':
foo.cc:43:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < g[temp].size(); i++) {
                         ~~^~~~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:61:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d", &n, &m, &s);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:63:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %lld", &x, &y, &z);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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