2019 Multi-University,HDU Day 4

Problem A

Solved by Kilo_5723. 00:12:16 (+1)

Problem B

Unsolved.

Problem C

Unsolved. (-3)

Problem D

Unsolved.

Problem E

Unsolved.

Problem F

Unsolved.

Problem G

Solved by Xiejiadong && Weaver_zhu. 02:45:41 (+1)

题意：判断十五数码问题是否无解。

题解：在 Xiejiadong 的强行误导下， Weaver_zhu 写了两个小时 A* 。

直接大力猜结论，大概模拟一下 $0$ 位置的变动。

根据 $0$ 所在位置的行列奇偶性和分行和列的逆序对数量奇偶行相同即可。

Problem H

Solved by Xiejiadong. 01:23:54 (+)

Problem I

Unsolved.

Problem J

Solved by Kilo_5723 && Xiejiadong. 04:09:28 (+1)