题意

题目链接

Sol

不要问我为什么发两篇blog，就是为了骗访问量

后缀数组的也比较好想，先把所有位置差分，然后在height数组中二分就行了

数据好水啊

// luogu-judger-enable-o2

#include<bits/stdc++.h>

using namespace std;

const int MAXN = 2e6 + 10;

const int INF = 2333;

inline int read() {

    char c = getchar(); int x = 0, f = 1;

    while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}

    while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();

    return x * f;

}

int T, N, M, a[MAXN], id[MAXN], rak[MAXN], tp[MAXN], tax[MAXN], H[MAXN], vis[MAXN], sa[MAXN], ti, mx;

void Qsort() {

    for(int i = 0; i <= M; i++) tax[i] = 0;

    for(int i = 1; i <= N; i++) tax[rak[i]]++;

    for(int i = 1; i <= M; i++) tax[i] += tax[i - 1];

    for(int i = N; i >= 1; i--) sa[tax[rak[tp[i]]]--] = tp[i];

}

void SuffixSort() {

    for(int i = 1; i <= N; i++) rak[i] = a[i], tp[i] = i;

    M = N + INF; Qsort();

    for(int w = 1, p = 0; p < N; w <<= 1, M = p) { p = 0;

        for(int i = 1; i <= w; i++) tp[++p] = N - i + 1;

        for(int i = 1; i <= N; i++) if(sa[i] > w) tp[++p] = sa[i] - w;

        Qsort(); swap(rak, tp); rak[sa[1]] = p = 1;

        for(int i = 2; i <= N; i++) rak[sa[i]] = (tp[sa[i]] == tp[sa[i - 1]] && tp[sa[i] + w] == tp[sa[i - 1] + w]) ? p : ++p;

    }

    for(int i = 1, k = 0; i <= N; i++) {

        if(k) k--; int j = sa[rak[i] - 1];

        while(a[i + k] == a[j + k]) k++;

        H[rak[i]] = k;

    }

}

bool check(int len) {

    ti++; int now = 0;

    for(int i = 1; i <= N; i++) {

        if(H[i] < len) {now = 0, ti++; continue;}

        if(vis[id[sa[i]]] != ti) vis[id[sa[i]]] = ti, now++;

        if(now == T) return 1;

    }

    return 0;

}

int main() {

    //freopen("a.in", "r", stdin);

    T = read();

    for(int i = 1; i <= T; i++) {

        int num = read() - 1, pre = read(); a[++N] = i; id[N] = i; mx = max(mx, num + 1);

        while(num--) a[++N] = read() - pre + INF, pre = a[N] + pre - INF, id[N] = i;

    }

    SuffixSort();

    int l = 1, r = mx, ans = 0;

    while(l <= r) {

        int mid = l + r >> 1;

        if(check(mid)) ans = mid, l = mid + 1;

        else r = mid - 1;

    }

    printf("%d", ans + 1);

    return 0;

}