Memeory limit exceded on G - Moving to the Capital (CodeForces)

https://codeforces.com/contest/1472/problem/G

I keep getting MLE on this submimision. I just can’t figure out why especially since the ML is 256 megabytes.

#include <bits/stdc++.h>
#define db(x) if(0)cerr << #x <<":"<<x<<"  "
using namespace std;

// ifstream fin (".in");
// ofstream fout(".out");

const int INF=1e9, MOD=1e9+7;
const int N=2e5+2;

unordered_set<int> g[N];
unordered_set<int> dag[N];
int best[N], special[N], d[N];

void dfsDag(int x){
    special[x]=d[x];
    for(int y:g[x]){
        special[x]=min(special[x],d[y]);
        if(d[y]>d[x]){
            dag[x].insert(y);
            dfsDag(y);
        }
    }
}
void dfsDp(int x){
    for(int y:dag[x]){
        dfsDp(y);
        best[x]=min(best[x], best[y]);
    }
    best[x]=min(best[x], special[x]);
}

void solve(){
    int n,m;
    cin>>n>>m;
    for(int i=1;i<=n;++i){
        g[i].clear();
        dag[i].clear();
    }
    fill(special+1, special+1+n, INF);
    fill(best, best+1+n, INF);
    fill(d, d+1+n, INF);
    for(int i=m; i--;){
        int x, y;
        cin>>x>>y;
        g[x].insert(y);
    }
    queue<int> q({1});
    d[1]=0;
    while(q.size()){
        int x=q.front();
        q.pop();
        for(int y:g[x]){
            if(d[x]+1<=d[y]){
                q.push(y);
                d[y]=d[x]+1;
            }
        }
    }
    dfsDag(1);
    dfsDp(1);
    for(int i=1;i<=n;++i)
        cout<<best[i]<<" ";
    cout<<"\n";
}

int main(){
#ifndef ONLINE_JUDGE
    freopen("g.in", "r", stdin);
    freopen("g.out", "w", stdout);
#endif
    int t;
    cin>>t;
    while(t--){
        solve();
    }
}