90pts TLE求助

#include <bits/stdc++.h>
using namespace std;
struct edge {
    int next, ed;
}b[1000010];
struct node {
    int x, step;
};
queue <node> q;
int n, Q, t[1010], nbs[1010], tot;
bool vis1[1010], vis2[1010][1010];
int read () {
        int x = 0, f = 1;
        char ch = getchar();
        while (ch < '0' || ch > '9') {
            if (ch == '-')
                f = -1;
            ch = getchar();
        }
        while (ch >= '0' && ch <= '9') {
            x = (x << 1) + (x << 3) + (ch - '0');
            ch = getchar();
        }
        return x * f;
}
void print (int x) {
    if (x < 0) {
        putchar('-');
        x = -x;
    }
    if (x > 9)
        print(x / 10);
    putchar(x % 10 + '0');
}
int bfs () {
    int ret = 0;
    for (int i = 1; i <= n; i++) {
        if (!t[i]) {
            q.push({i, 1});
        }
    }
    while (!q.empty()) {
        node cur = q.front();
        ret = max(ret, cur.step);
        for (int k = nbs[cur.x]; k; k = b[k].next) {
            int u = b[k].ed;
            t[u]--;
            if (!t[u]) {
                q.push({u, cur.step + 1});
            }
        }
        q.pop();
    }
    return ret;
}
int main () {
    n = read(), Q = read();
    while (Q--) {
        memset(vis1, 0, sizeof(vis1));
        int s, l, r;
        s = read();
        for (int i = 1, x; i <= s; i++) {
            x = read();
            if (i == 1) {
                l = x;
            }
            if (i == s) {
                r = x;
            }
            vis1[x] = true;
        }
        for (int i = l; i <= r; i++) {
            if (vis1[i]) {
                for (int j = l; j <= r; j++) {
                    if (!vis1[j] && !vis2[i][j]) {
                        vis2[i][j] = true;
                        t[j]++;
                        b[++tot].ed = j; b[tot].next = nbs[i]; nbs[i] = tot;
                    }
                }
            }
        }
    }
    print(bfs());
    return 0;
}

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