#include<bits/stdc++.h>

using namespace std;
const int maxm = 2e5+7;
vector<int>edge[maxm],rev[maxm];
int inv[maxm],ans[maxm],L[maxm],R[maxm],n,m;
int tinv[maxm],trev[maxm],tmp[maxm];
void init(){
    for(int i=1;i<=n;i++){
        edge[i].clear();
        rev[i].clear();
        inv[i] = ans[i] = L[i] = R[i] = 0;
        tinv[i] = trev[i] = 0;
        tmp[i] = 0;
    }
}
void topo(){
    //跑一遍拓扑，看看是不是DAG
    queue<int>Q;
    for(int i=1;i<=n;i++){
        if(inv[i] == 0) Q.push(i);
    }
    while(Q.size()){
        int now = Q.front();
        Q.pop();
        for(auto u:edge[now]){
            --inv[u];
            if(inv[u] == 0){
                Q.push(u);
            }
        }
    }
}
void print(){
    for(int i=1;i<=n;i++) cout<<ans[i];
    cout<<"\n";
}
int dfs1(int now){
    if(tmp[now]) return 0;
    tmp[now] = 1;
    for(auto u:edge[now]){
        tmp[now] += dfs1(u);
    }
    return tmp[now];
}
int dfs2(int now){
    if(tmp[now]) return 0;
    tmp[now] = 1;
    for(auto u:rev[now]){
        tmp[now] += dfs2(u);
    }
    return tmp[now];
}
void calc1(){
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++) tmp[j] = 0;
        dfs1(i);
        L[i] = tmp[i];
    }
}
void calc2(){
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++) tmp[j] = 0;
        dfs2(i);
        R[i] = tmp[i];
    }
}
void solve(){
    cin>>n>>m;
    init();
    for(int i=1;i<=m;i++){
        int u,v;cin>>u>>v;
        edge[v].push_back(u);
        rev[u].push_back(v);
        inv[u]++;tinv[u]++;
        trev[v]++;
    }
    topo();
    
    for(int i=1;i<=n;i++){
        if(inv[i]){
            //说明不是DAG,直接返回false
            print();
            return;
        }
    }
    calc1();
    calc2();
    for(int i=1;i<=n;i++){
        if(L[i]<=(n+1)/2 and R[i]<=(n+1)/2) ans[i] = 1;
    }
    print();
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    int T;cin>>T;
    while(T--) solve();
    return 0;
}