foo.cc: In function 'int main()':
foo.cc:13:21: warning: left operand of comma operator has no effect [-Wunused-value]
   13 |  for(int i=1,j=i+1;i<n,j<=n;i++,j++)
      |                    ~^~
foo.cc:15:28: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   15 |    if(a[i]<a[j]||a[i]==a[j]&&b[i]>b[j])
      |                  ~~~~~~~~~~^~~~~~~~~~~

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