HDU 4901 The Romantic Hero (two-dimensional dp)

HDU 4901 The Romantic Hero (two-dimensional dp)

Give you n numbers and divide them into two portions. The elements in one portion of the front are exclusive or, and the elements in the other portion are matched. Calculate the number according to the given order. The subscript of all the elements in the following column must be larger than the preceding one. Ask you how many ways to put elements to make the previous exclusive OR value equal to the following value.

Dp [x] [y] indicates the number of methods to obtain the number of y in step x.

However, you must note that you cannot use the dp array to store the number. You need to divide the number of times from the previous layer and the number of times you can reach this layer. Then, multiply the number of the first and second sets when the sum is obtained. Pay attention to the side multiplication and edge multiplication.

By the way, give a group of data:

4

3 3 3 3

Output: 12.

 

The Romantic Hero Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 131072/131072 K (Java/Others)
Total Submission (s): 459 Accepted Submission (s): 173


Problem Description There is an old country and the king fell in love with a dedevil. the dedevil always asks the king to do some crazy things. although the king used to be wise and beloved by his people. now he is just like a boy in love and can't refuse any request from the dedevil. also, this dedevil is looking like a very cute Loli.

You may wonder why this country has such an interesting tradition? It has a very long story, but I won't tell you :).

Let us continue, the party princess's knight win the algorithm contest. When the dedevil hears about that, she decided to take some action.

But before that, there is another party arose recently, the 'mengmengda 'party, everyone in this party feel everything is 'mengmengda' and acts like a' MengMengDa' guy.

While they are very pleased about that, it brings should people in this kingdom troubles. So they decided to stop them.

Our hero z * p come again, actually he is very good at Algorithm contest, so he invites the leader of the 'mengda' party xiaod * o to compete in an algorithm contest.

As z * p is both handsome and talkative, he has cute girl friends to deal with, on the contest day, he find he has 3 dating to complete and have no time to compete, so he let you to solve the problems for him.

And the easiest problem in this contest is like that:

There is n number a_1, a_2 ,..., a_n on the line. you can choose two set S (a_s1, a_s2 ,.., a_sk) and T (a_t1, a_t2 ,..., a_tm ). each element in S shoshould be at the left of every element in T. (si <tj for all I, j ). S and T shouldn't be empty.

And what we want is the bitwise XOR of each element in S is equal to the bitwise AND of each element in T.

How many ways are there to choose such two sets? You shoshould output the result modulo 10 ^ 9 + 7.

Input The first line contains an integer T, denoting the number of the test cases.
For each test case, the first line contains a integers n.
The next line contains n integers a_1, a_2,..., a_n which are separated by a single space.

N <= 10 ^ 3, 0 <= a_ I <1024, T <= 20.
Output For each test case, output the result in one line.
Sample Input

231 2 341 2 3 3

Sample Output

1 4

Author WJMZBMR
Source 2014 Multi-University Training Contest 4

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