#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

typedef priority_queue<int, vector<int>, greater<int>> pqmin;

const int MOD = 1e9+7;

int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }

int lcm(int a, int b) { return (a / gcd(a, b)) * b; }

int modpow(int a, int b, int mod = MOD) {

int res = 1;

while (b) {

if (b & 1) res = (res * a) % mod;

a = (a * a) % mod;

b >>= 1;

}

return res;

}

vector<int> sieve(int n) {

vector<int> isPrime(n + 1, 1);

isPrime[0] = isPrime[1] = 0;

for (int i = 2; i*i <= n; i++)

if (isPrime[i])

for (int j = i*i; j <= n; j += i)

isPrime[j] = 0;

return isPrime;

}

bool isPrime(int n) {

if (n <= 1) return false;

if (n <= 3) return true;

if (n % 2 == 0 || n % 3 == 0) return false;

for (int i = 5; i * i <= n; i += 6) {

if (n % i == 0 || n % (i + 2) == 0)

return false;

}

return true;

}

void solve(){

int n;

cin>>n;

string s;

cin>>s;

int k=0;

vector<int> ans;

for(int i=0;i<n;i++){

if(s[i]=='0') {

k++;

ans.push_back(i+1);

}

}

cout<<k<<endl;

for(int i=0;i<ans.size();i++) cout<<ans[i]<<" ";

cout<<endl;

}

int main(){

ios::sync_with_stdio(0);

cin.tie(0);

int t = 1;

cin>>t;

while (t--)

{

solve();

}

}