foo.cc: In function 'LL Dinic(int, int)':
foo.cc:79:9: warning: unused variable 'cnt' [-Wunused-variable]
     int cnt = 0;
         ^~~
foo.cc: In function 'int main()':
foo.cc:111:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d", &_graph[i][j]);
             ~~~~~^~~~~~~~~~~~~~~~~~~~~