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6052：To my boyfriend

题目描述
Dear Liao

I never forget the moment I met with you. You carefully asked me: "I have a very difficult problem. Can you teach me?". I replied with a smile, "of course". You replied:"Given a matrix, I randomly choose a sub-matrix, what is the expectation of the number of **different numbers** it contains?"

Sincerely yours,
Guo
输入解释
The first line of input contains an integer T(T≤8) indicating the number of test cases.
Each case contains two integers, n and m (1≤n, m≤100), the number of rows and the number of columns in the grid, respectively.
The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains g_i,j (0≤ g_i,j < n*m).
输出解释
Each case outputs a number that holds 9 decimal places.
输入样例 
1
2 3
1 2 1
2 1 2
输出样例 
1.666666667
提示
6(size = 1) + 14(size = 2) + 4(size = 3) + 4(size = 4) + 2(size = 6) = 30  / 18 = 6(size = 1) + 7(size = 2) + 2(size = 3) + 2(size = 4) + 1(size = 6)
来自杭电HDUOJ的附加信息
Recommend liuyiding
该题目是Virtual Judge题目，来自 杭电HDUOJ
题目来源 2017 Multi-University Training Contest - Team 2
源链接： HDU-6052
最后修改于 2020-10-25T23:27:53+00:00 由爬虫自动更新
共提交 0 次
通过率 --%
时间上限 内存上限
2000/1000MS(Java/Others) 32768/32768K(Java/Others)