#include <bits/stdc++.h>
using namespace std;

#define x first
#define y second
typedef pair<int, int> PII;
typedef long long ll;

void solve()
{
    int n, m;
    cin >> n >> m;
    vector<vector<int>> g(n + 1), rg = g;
    vector<int> din(n + 1);
    for(int i = 0; i < m; i++)
    {
        int u, v;
        cin >> u >> v;
        g[u].push_back(v);
        rg[v].push_back(u);
        din[v]++;
    }
    queue<int> q;
    for(int i = 1; i <= n; i++) if(!din[i]) q.push(i);
    queue<int> Q = q;    
    while(q.size())
    {
        auto u = q.front();
        q.pop();
        for(auto v : g[u]) if(!--din[v]) q.push(v);
    }
    if(*max_element(din.begin(), din.end())) 
    {
        for(int i = 1; i <= n; i++) cout << 0;
        cout << '\n';
        return;
    }
    auto get = [&](vector<vector<int>> &g)
    {
        vector<int> d(n + 1);
        for(int u = 1; u <= n; u++) for(auto v : g[u]) d[v]++;
        vector<int> top;
        queue<int> q;
        for(int i = 1; i <= n; i++) if(!d[i]) q.push(i), top.push_back(i);
        while(q.size())
        {
            auto u = q.front();
            q.pop();
            for(auto v : g[u]) if(!--d[v]) q.push(v), top.push_back(v);
        }
        vector<int> pre(n + 1);
        for(auto u : top) for(auto v : g[u]) pre[v] += pre[u] + 1;
        return pre;
    };
    auto pre = get(g), nxt = get(rg);
    for(int i = 1; i <= n; i++) 
        if(pre[i] <= n / 2 && nxt[i] <= n / 2) cout << 1;
        else cout << 0;
    cout << '\n';
}

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