foo.cc: In function 'int main()':
foo.cc:17:22: warning: comparison of integer expressions of different signedness: 'int' and 'long long unsigned int' [-Wsign-compare]
   17 |         for(int i=0;i<n;i++)
      |                     ~^~
foo.cc:19:22: warning: comparison of integer expressions of different signedness: 'int' and 'long long unsigned int' [-Wsign-compare]
   19 |         for(int i=0;i<n;i++)
      |                     ~^~
foo.cc:22:30: warning: comparison of integer expressions of different signedness: 'int' and 'long long unsigned int' [-Wsign-compare]
   22 |                 for(int y=1;y<=a[i];y++)
      |                             ~^~~~~~

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