C. A-B Palindrometime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou are given a string s consisting of the characters '0', '1', and '?'. You need to replace all the characters with '?' in the string s by '0' or '1' so that the string becomes a palindrome and has exactly a characters '0' and exactly b characters '1'. Note that each of the characters '?' is replaced independently from the others.A string t of length n is called a palindrome if the equality t[i] = t[n-i+1] is true for all i (1 \le i \le n).For example, if s="01?????0", a=4 and b=4, then you can replace the characters '?' in the following ways:   "01011010";  "01100110". For the given string s and the numbers a and b, replace all the characters with '?' in the string s by '0' or '1' so that the string becomes a palindrome and has exactly a characters '0' and exactly b characters '1'.InputThe first line contains a single integer t (1 \le t \le 10^4). Then t test cases follow.The first line of each test case contains two integers a and b (0 \le a, b \le 2 \cdot 10^5, a + b \ge 1).The second line of each test case contains the string s of length a+b, consisting of the characters '0', '1', and '?'.It is guaranteed that the sum of the string lengths of s over all test cases does not exceed 2 \cdot 10^5.OutputFor each test case, output:   "-1", if you can't replace all the characters '?' in the string s by '0' or '1' so that the string becomes a palindrome and that it contains exactly a characters '0' and exactly b characters '1';  the string that is obtained as a result of the replacement, otherwise. If there are several suitable ways to replace characters, you can output any.ExampleInput
9
4 4
01?????0
3 3
??????
1 0
?
2 2
0101
2 2
01?0
0 1
0
0 3
1?1
2 2
?00?
4 3
??010?0
Output
01011010
-1
0
-1
0110
-1
111
1001
0101010

9
4 4
01?????0
3 3
??????
1 0
?
2 2
0101
2 2
01?0
0 1
0
0 3
1?1
2 2
?00?
4 3
??010?0

01011010 -1 0 -1 0110 -1 111 1001 0101010 
['constructive algorithms', 'implementation', 'strings', '*1200']