If s1 [ i ] != s2 [ i ] , then inverse the characters at i snd ( i + 1 ) positions in s1 .
if ( s1 [ i ] == '1' ) : NEW_LINE INDENT s1 [ i ] = '0' NEW_LINE DEDENT else : NEW_LINE INDENT s1 [ i ] = '1' NEW_LINE DEDENT if ( s1 [ i + 1 ] == '1' ) : NEW_LINE INDENT s1 [ i + 1 ] = '0' NEW_LINE DEDENT else : NEW_LINE INDENT s1 [ i + 1 ] = '1' NEW_LINE DEDENT