CF1353B Two Arrays And Swaps

You are given two arrays $ a $ and $ b $ both consisting of $ n $ positive (greater than zero) integers. You are also given an integer $ k $ . In one move, you can choose two indices $ i $ and $ j $ ( $ 1 \le i, j \le n $ ) and swap $ a_i $ and $ b_j $ (i.e. $ a_i $ becomes $ b_j $ and vice versa). Note that $ i $ and $ j $ can be equal or different (in particular, swap $ a_2 $ with $ b_2 $ or swap $ a_3 $ and $ b_9 $ both are acceptable moves). Your task is to find the maximum possible sum you can obtain in the array $ a $ if you can do no more than (i.e. at most) $ k $ such moves (swaps). You have to answer $ t $ independent test cases.

The first line of the input contains one integer $ t $ ( $ 1 \le t \le 200 $ ) — the number of test cases. Then $ t $ test cases follow. The first line of the test case contains two integers $ n $ and $ k $ ( $ 1 \le n \le 30; 0 \le k \le n $ ) — the number of elements in $ a $ and $ b $ and the maximum number of moves you can do. The second line of the test case contains $ n $ integers $ a_1, a_2, \dots, a_n $ ( $ 1 \le a_i \le 30 $ ), where $ a_i $ is the $ i $ -th element of $ a $ . The third line of the test case contains $ n $ integers $ b_1, b_2, \dots, b_n $ ( $ 1 \le b_i \le 30 $ ), where $ b_i $ is the $ i $ -th element of $ b $ .

For each test case, print the answer — the maximum possible sum you can obtain in the array $ a $ if you can do no more than (i.e. at most) $ k $ swaps.

In the first test case of the example, you can swap $ a_1 = 1 $ and $ b_2 = 4 $ , so $ a=[4, 2] $ and $ b=[3, 1] $ . In the second test case of the example, you don't need to swap anything. In the third test case of the example, you can swap $ a_1 = 1 $ and $ b_1 = 10 $ , $ a_3 = 3 $ and $ b_3 = 10 $ and $ a_2 = 2 $ and $ b_4 = 10 $ , so $ a=[10, 10, 10, 4, 5] $ and $ b=[1, 9, 3, 2, 9] $ . In the fourth test case of the example, you cannot swap anything. In the fifth test case of the example, you can swap arrays $ a $ and $ b $ , so $ a=[4, 4, 5, 4] $ and $ b=[1, 2, 2, 1] $ .