foo.cc: In function 'int dijkstra(int, int)':
foo.cc:27:51: warning: 'u' may be used uninitialized [-Wmaybe-uninitialized]
   27 |                                 if (dist[j]>dist[u] + arr[u][j])
      |                                             ~~~~~~^
foo.cc:7:32: note: 'u' was declared here
    7 |         int dist[2501],s[2501],u;
      |                                ^

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