#include<bits/stdc++.h>
#define ll long long
#define all(x) x.begin(), x.end()
#define lowbit(i) ((i)&(-i))
#define pii pair<int,int>
#define endl '\n'
#define mk(x,y) make_pair(x,y)
#define popcount(x) __builtin_popcount(x)
const double pi=3.14159265358979323846;
const double eps=1e-9;
const int inf=1e9;
const long long INF=4e18;
const int mod=1e9+7;
using namespace std;
const int N=1e5+10;

void solve()
{
    int n,m;
    cin>>n>>m;
    vector<vector<int>>e(n+1),g(n+1);
    bool flag=false;
    for(int i=1;i<=m;i++){
    	int a,b;
    	cin>>a>>b;
    	e[a].push_back(b);
        g[b].push_back(a);
        if(a==b)flag=1;
    }
    if(flag){
        for(int i=1;i<=n;i++){
            cout<<"0";
        }
        cout<<endl;
        return;
    }
    int cnt=n/2;
    vector<int>ans(n+1,1);
    vector<int>pre(n+1),suf(n+1);//前驱结点与后继结点的个数
    vector<int>vis(n+1);
    auto bfs=[&](int u){
        queue<int>q;
        q.push(u);
        vis[u]=1;
        while(q.size()){
            int x=q.front();q.pop();
            for(int v:e[x]){
                if(v==u)return false;
                if(vis[v]==u)continue;
                vis[v]=u;
                q.push(v);
                pre[v]++;suf[u]++;
            }
        }
        return true;
    };
    for(int i=1;i<=n;i++){
        if(!bfs(i)){
            for(int i=1;i<=n;i++){
                cout<<"0";
            }
            cout<<endl;
            return;
        }
    }

    // for(int i=1;i<=n;i++){
    //     cout<<pre[i]<<" "<<suf[i]<<endl;
    // }
    for(int i=1;i<=n;i++){
        if(suf[i]>n/2||pre[i]>n/2)ans[i]=0;
    }
    for(int i=1;i<=n;i++){
        cout<<ans[i];
    }
    cout<<endl;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    
    int T=1;
    cin>>T;
    while(T--){
        solve();
    }
    return 0;
}