Are there any 'tricks' to speed up sampling of a very large knapsack combination type prob?

前端未结

关注

 9  2000

情话喂你 2020-12-29 10:21

UPDATE: I have realized the problem below is not possible to answer in its current form because of the large amount of data involved(15k+ items). I just found out, the

9条回答

無奈伤痛 (楼主)

2020-12-29 10:39

There are 137 unique values (ignoring the repeats) in the sample data given.

If you concede that nearly any combination of 30 distinct values pulled from the data at random can be massaged into at least one valid solution by adjusting the coefficients, then there must be at least C(137,30)=1.54E30 solutions with exactly 30 terms (and another 5.31E30 with 31 terms, 1.76E31 with 32 terms, 5.60E31 with 33 terms, etc).

So, if your goal is just a sampling of valid solutions, and not an impossible exhaustive list, then I submit that an ideal approach is to select your target number of terms at random and then adjust their coefficients to reach the target value to produce a single sample, and repeat for the desired number of samples.

Below is a program that applies this technique. On my fairly modest laptop (1.3Ghz AMD E-300), I produced 15000 unique solutions in 2.249 seconds targeting 32 terms per sample.

import java.util.Arrays; import java.util.HashMap; import java.util.Map; import java.util.Map.Entry; import java.util.Random; import java.util.TreeMap; public class ComboGen { private static final int[] data = { -193, -138, -92, -80, -77, -70, -63, -61, -60, -56, -56, -55, -54, -54, -51, -50, -50, -50, -49, -49, -48, -46, -45, -44, -43, -43, -42, -42, -42, -42, -41, -41, -40, -40, -39, -38, -38, -38, -37, -37, -37, -37, -37, -36, -36, -36, -35, -34, -34, -34, -34, -34, -34, -34, -33, -33, -33, -32, -32, -32, -32, -32, -32, -32, -32, -31, -31, -31, -31, -31, -31, -31, -30, -30, -30, -30, -30, -29, -29, -29, -29, -29, -29, -29, -29, -29, -28, -28, -28, -28, -27, -27, -27, -27, -26, -26, -26, -26, -26, -26, -25, -25, -25, -25, -25, -25, -25, -25, -24, -24, -24, -24, -24, -24, -24, -24, -24, -24, -23, -23, -23, -23, -23, -23, -23, -23, -22, -22, -22, -22, -22, -22, -22, -22, -22, -21, -21, -21, -21, -21, -21, -21, -20, -20, -20, -20, -20, -20, -20, -19, -19, -19, -19, -19, -19, -19, -19, -19, -19, -19, -19, -19, -19, -18, -18, -18, -18, -18, -18, -18, -18, -18, -18, -18, -18, -18, -18, -18, -18, -18, -17, -17, -17, -17, -17, -17, -17, -17, -17, -17, -17, -17, -17, -17, -17, -17, -17, -16, -16, -16, -16, -16, -16, -16, -16, -16, -16, -16, -16, -16, -16, -16, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -15, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -14, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -13, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -12, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -11, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -10, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -8, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -7, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -6, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -5, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 20, 20, 20, 20, 20, 20, 20, 20, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 26, 26, 26, 26, 26, 26, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 28, 28, 28, 28, 28, 28, 29, 29, 29, 29, 30, 30, 30, 30, 30, 30, 30, 31, 31, 31, 31, 31, 32, 32, 32, 32, 33, 33, 33, 33, 34, 34, 34, 34, 34, 34, 34, 35, 35, 35, 35, 36, 36, 36, 36, 37, 37, 38, 39, 39, 39, 40, 41, 41, 41, 41, 41, 42, 42, 43, 43, 44, 45, 45, 46, 47, 47, 48, 48, 49, 49, 50, 54, 54, 54, 55, 55, 56, 56, 57, 57, 57, 57, 57, 58, 58, 58, 59, 60, 66, 67, 68, 70, 72, 73, 73, 84, 84, 86, 92, 98, 99, 105, 114, 118, 120, 121, 125, 156 }; private static Map buildCounts(int[] rawData) { Map buckets = new TreeMap(); int i = 0; for (i = 0; i < rawData.length; i++) { if (buckets.containsKey(rawData[i])) { buckets.put(rawData[i], buckets.get(rawData[i]) + 1); } else { buckets.put(rawData[i], 1); } } weights = new int[buckets.size()]; counts = new int[buckets.size()]; i = 0; for (Entry entry : buckets.entrySet()) { weights[i] = entry.getKey(); counts[i] = entry.getValue(); i++; } return buckets; } private static int[] weights; private static int[] counts; private static Random random = new Random(System.nanoTime()); private static int[] placeChips(int[] chips, int targetPairs) { int unplaced = targetPairs; int[] placements = new int[unplaced]; Arrays.fill(chips, 0); if (unplaced > chips.length) { throw new IllegalStateException("Coefficient pairs must not exceed unique data values."); } while (unplaced > 0) { int idx = random.nextInt(counts.length); if (chips[idx] == 0) { chips[idx] = 1 + random.nextInt(100); unplaced--; } } int ppos = 0; for (int cpos = 0; cpos < chips.length; cpos++) { if (chips[cpos] > 0) { placements[ppos++] = cpos; } } return placements; } static int sum(int[] chips) { int sum = 0; for (int i = 0; i < chips.length; i++) { sum += weights[i] * chips[i]; } return sum; } public static void adjustFactors(int[] chips, int[] placements, int target) { int sum = sum(chips); Map weightIdx = new HashMap(); for (int placement : placements) { weightIdx.put(weights[placement], placement); } while (sum != target) { // System.out.print(sum + ","); int idx = 0; if ((sum > target) && weightIdx.containsKey(sum - target) && (chips[weightIdx.get(sum - target)] > 1)) { idx = weightIdx.get(sum - target); } else if ((sum < target) && weightIdx.containsKey(sum - target) && (chips[weightIdx.get(sum - target)] > 1)) { idx = weightIdx.get(sum - target); } else if ((sum > target) && weightIdx.containsKey(target - sum) && chips[weightIdx.get(target - sum)] < 100) { idx = weightIdx.get(target - sum); } else if ((sum < target) && weightIdx.containsKey(target - sum) && chips[weightIdx.get(target - sum)] < 100) { idx = weightIdx.get(target - sum); } else { idx = placements[random.nextInt(placements.length)]; } int weight = weights[idx]; if (sum < target) { if (weight > 0 && chips[idx] < 100) { chips[idx]++; sum += weight; } else if (weight < 0 && chips[idx] > 1) { chips[idx]--; sum -= weight; } } else { if (weight > 0 && chips[idx] > 1) { chips[idx]--; sum -= weight; } else if (weight < 0 && chips[idx] < 100) { chips[idx]++; sum += weight; } } } } private static String oneRandomSet(int targetSum, int targetPairs) { int[] chips = new int[counts.length]; int[] placements = placeChips(chips, targetPairs); adjustFactors(chips, placements, targetSum); int sum = sum(chips); StringBuffer sb = new StringBuffer(); for (int placement : placements) { sb.append(weights[placement]); sb.append(" * "); sb.append(chips[placement]); sb.append(" + "); } sb.setLength(sb.length() - 2); sb.append(" = "); sb.append(sum); sb.append("\n"); return sb.toString(); } public static void main(String[] ARGV) { int targetSum = 5000; int targetPairs = 32; int targetResults = 15000; // Produce this many solutions buildCounts(data); StringBuffer sb = new StringBuffer(); long timer = System.nanoTime(); for (int i = 0; i < targetResults; i++) { sb.append(oneRandomSet(targetSum, targetPairs)); } double seconds = (System.nanoTime() - timer) / 1000000000d; double millisPerSol = 1000 * seconds / targetResults; System.out.println(sb.toString()); System.out.println(String.format("%d solutions in %1.3f seconds @ %1.3f millis per sol", targetResults, seconds, millisPerSol)); } }

0 讨论(0)

查看其它9个回答

发布评论:

提交评论

加载中...

验证码

看不清?

提交回复