PrefixXor [ i ] = Xor of all arr elements till i ' th ▁ index ▁ PrefixXor [ n - 1 ] ▁ ▁ ^ ▁ PrefixXor [ i ] ▁ = ▁ Xor ▁ of ▁ all ▁ elements ▁ ▁ from ▁ i + 1' th index to n - 1 'th index
if ( PrefixXor [ i ] + ( PrefixXor [ n - 1 ] ^ PrefixXor [ i ] ) > sum ) { sum = PrefixXor [ i ] + ( PrefixXor [ n - 1 ] ^ PrefixXor [ i ] ) ; index = i ; } }