问题 C: Simple Set Problem

内存限制：256 MB 时间限制：3 S

题面：传统评测方式：文本比较上传者：

提交：4 通过：2

Given $k$ non empty multiple sets, each multiple set only contains integers with absolute values not exceeding $1 0^9$ .

It is required to select exactly one number from each multiple set to form an array $(a_{1}, a_{2}, \dots, a_{k})$ with a length of $k$ .

Assuming $d = max (a_{1}, a_{2}, \dots, a_{k}) - min (a_{1}, a_{2}, \dots, a_{k})$ .Please calculate the minimum $d$ .

Each test contains multiple test cases.The first line of input contains a single integer $t (1 \leq t \leq 1 0^6)$ ---the number of test cases.The description of test cases follows.

The first line of each test case contains a single integer $k (1 \leq k \leq 1 0^6)$ —— the number of multiple sets.

The following $k$ lines of each test case first read in a parameter $c_{i}$ —— indicating the size of the i-th multiple set, followed by $c_{i}$ integers with absolute values not exceeding $1 0^9$ —— indicating the elements of the $i$ -th multiple set.

Guarantee that $\sum_{i = 1 k} c_{i}$ for each test case does not exceed $1 0^{6}$ , the sum of $\sum_{i = 1 k} c_{i}$ for all test cases does not exceed $4 \times 1 0^6$ .

For each testcase, output an integer representing the answer, which is the minimum

d

3
2
1 6
3 -7 7 10
4
9 -5 -9 2 8 5 4 3 3 8
2 10 8
1 -7
3 1 6 10
1
1 9

1
15
0

问题 C: Simple Set Problem

题目描述

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问题 C: Simple Set Problem

题目描述

输入格式

输出格式

输入样例 复制

输出样例 复制

输入样例复制

输出样例复制