# include<bits/stdc++.h>

using namespace std;
# define l long long 
# define db double 
# define rep(i,a,b) for(l i=a;i<b;i++)
# define vi vector<l>
# define vvi vector<vi>
# define vsi vector<set<l> >
# define pb push_back
# define mp make_pair
# define ss second
# define ff first
# define pii pair<l,l>
# define trvi(v,it) for(vi::iterator it=v.begin();it!=v.end();++it)
# define read(a) freopen(a,"r",stdin)
# define write(a) freopen(a,"w",stdout)
# define io ios::sync_with_stdio(false)

template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ' ' << p.second << ')'; }

const bool MULTIPLE_TEST_CASES = true;

const l MOD=1e9+7;
const l N=1e5+5;
const l INF=1e12;

void solve() {
	l n;
	cin>>n;
	string a(n,' '),b;
	cin>>b;
	a[0] = '1';
	rep(i,1,n) {
		l prev = (a[i-1]-'0') + (b[i-1] - '0');
		l cur = b[i] - '0';
		if(prev==cur+1) {
			a[i] = '0';
		} else {
			a[i] = '1';
		}
	}
	cout<<a<<"\n";
	return;
}


int main(){
	io;
	int t=1;
	if (MULTIPLE_TEST_CASES) cin>>t;
	rep(i,0,t) {
		solve();
	}

	return 0;
}
