Codeforces Round 740 (Div. 2, based on VK Cup 2021 - Final (Engine))
C
Deep Down Below
Codeforces
1300
原题
← BD1 →
翻译中…

In a certain video game, the player controls a hero characterized by a single integer value: power. The hero will have to beat monsters that are also characterized by a single integer value: armor.

翻译中…

On the current level, the hero is facing $n$ caves. To pass the level, the hero must enter all the caves in some order, each cave exactly once, and exit every cave safe and sound. When the hero enters cave $i$, he will have to fight $k_i$ monsters in a row: first a monster with armor $a_{i, 1}$, then a monster with armor $a_{i, 2}$ and so on, finally, a monster with armor $a_{i, k_i}$.

翻译中…

The hero can beat a monster if and only if the hero's power is strictly greater than the monster's armor. If the hero can't beat the monster he's fighting, the game ends and the player loses. Note that once the hero enters a cave, he can't exit it before he fights all the monsters in it, strictly in the given order.

翻译中…

Each time the hero beats a monster, the hero's power increases by $1$.

翻译中…

Find the smallest possible power the hero must start the level with to be able to enter all the caves in some order and beat all the monsters.

翻译中…

Input

翻译中…

Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 10^5$). Description of the test cases follows.

翻译中…

The first line of each test case contains a single integer $n$ ($1 \le n \le 10^5$) — the number of caves.

翻译中…

The $i$-th of the next $n$ lines contains an integer $k_i$ ($1 \le k_i \le 10^5$) — the number of monsters in the $i$-th cave, followed by $k_i$ integers $a_{i, 1}, a_{i, 2}, \ldots, a_{i, k_i}$ ($1 \le a_{i, j} \le 10^9$) — armor levels of the monsters in cave $i$ in order the hero has to fight them.

翻译中…

It is guaranteed that the sum of $k_i$ over all test cases does not exceed $10^5$.

翻译中…

Output

翻译中…

For each test case print a single integer — the smallest possible power the hero must start the level with to be able to enter all the caves in some order and beat all the monsters.

翻译中…

Note

翻译中…

In the first test case, the hero has to beat a single monster with armor $42$, it's enough to have power $43$ to achieve that.

翻译中…

In the second test case, the hero can pass the level with initial power $13$ as follows:

翻译中…
  • enter cave $2$:
  • beat a monster with armor $12$, power increases to $14$;
    • beat a monster with armor $11$, power increases to $15$;
  • enter cave $1$:
  • beat a monster with armor $10$, power increases to $16$;
    • beat a monster with armor $15$, power increases to $17$;
    • beat a monster with armor $8$, power increases to $18$.
翻译中…

样例

Input #1
2
1
1 42
2
3 10 15 8
2 12 11
Output #1
43
13
InputCopy OutputCopy
题目信息
题号
1561C
时间限制
2 s
内存限制
512 MB
标签
二分
贪心
排序

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。