/in/foo.cc: In function 'void Insert(const int&)':
/in/foo.cc:72:6: warning: operation on 'tot' may be undefined [-Wsequence-point]
  key[++tot] = sum[tot] = cost, sze[tot] = 1;
      ^~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:111:21: warning: format '%d' expects argument of type 'int', but argument 2 has type 'll {aka long long int}' [-Wformat=]
  printf("%I64d", ans);
                     ^