for test case
1
5
1010111010
i think answer should be 7
Scanner s = new Scanner(System.in);
int t = s.nextInt();
while(t–> 0) {
int n = s.nextInt();
String str = s.next();
int temp = str.length();
int a = 0;
int b = 0;
for(int i = 0; i < 2 * n; i += 2) {
temp = temp - i;
if(a - b > n / 2) {
System.out.println(i);
break;
}
if(str.charAt(i) == '1')
a++;
if(a - b > n / 2 && temp < n / 2) {
System.out.println(i + 1);
break;
}
if(str.charAt(i + 1) == '1')
b++;
}
if(a == b)
System.out.println(2 * n);