DFS CCPC2017 南宁I题

The designers have come up with a new simple game called “Rake It In”. Two players, Alice and Bob, initially select an integer k and initialize a score indicator. An $\times 44×4 board is created with 16 values placed on the board. Starting with player Alice, each player in a round selects a 2 \times 22×2 region of the board, adding the sum of values in the region to the score indicator, and then rotating these four values 9090 degrees counterclockwise.$

After

In order to test how good this game is, you are hired to write a program which can play the game. Specifically, given the starting configuration, they would like a program to determine the final score when both players are entirely rational.

Input

The input contains several test cases and the first line provides an integer $\le t \le 200)t(1≤t≤200)which is the number of test cases.$

Each case contains five lines. The first line provides the integer $\le k \le 3)k(1≤k≤3). Each of the following four lines contains four integers indicating the values on the board initially. All values are integers between 11 to 1010.$

Output

For each case, output an integer in a line which is the predicted final score.

样例输入

样例输出

之前搜有大佬说需要用到alpha-beta剪枝，但是数据范围非常小，似乎不需要

还是贴个链接吧，如果有需要的可以看看https://blog.csdn.net/qq_27008079/article/details/60869054

暴力DFS，回溯，感觉没太多好讲的

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 const double pi=acos(-1);
 5 const int mod=1e9+7;
 6 const int inf=1<<30;
 7 const int maxn=1e5+7;
 8 int a[4][4];
 9 int k;
10 int val(int i,int j){
11     return a[i][j]+a[i+1][j]+a[i][j+1]+a[i+1][j+1];
12 }
13 void rotat(int i,int j){
14     int a1=a[i][j],a2=a[i][j+1],a3=a[i+1][j],a4=a[i+1][j+1];
15     a[i][j]=a2,a[i][j+1]=a4,a[i+1][j]=a1,a[i+1][j+1]=a3;
16 }
17 void retat(int i,int j){
18     int a1=a[i][j],a2=a[i][j+1],a3=a[i+1][j],a4=a[i+1][j+1];
19     a[i][j]=a3,a[i][j+1]=a1,a[i+1][j]=a4,a[i+1][j+1]=a2;
20 }
21 int dfs(int t){
22     int ans;
23     if(t==2*k-1){
24         ans=inf;
25         for(int i=0;i<3;i++)
26         for(int j=0;j<3;j++)
27         ans=min(ans,val(i,j));
28         return ans;
29     }
30     else if(t%2==0){
31         ans=0;
32         for(int i=0;i<3;i++)
33         for(int j=0;j<3;j++){
34             rotat(i,j);
35             int tmp=val(i,j);
36             ans=max(ans,tmp+dfs(t+1));
37             retat(i,j);
38         }
39     }
40     else{
41         ans=inf;
42         for(int i=0;i<3;i++)
43         for(int j=0;j<3;j++){
44             rotat(i,j);
45             int tmp=val(i,j);
46             ans=min(ans,tmp+dfs(t+1));
47             retat(i,j);
48         }
49     }
50     return ans;
51 }
52 int main(){
53     int T;scanf("%d",&T);
54     while(T--){
55         scanf("%d",&k);
56         for(int i=0;i<4;i++){
57             for(int j=0;j<4;j++){
58                 scanf("%d",&a[i][j]);
59             }
60         }
61         cout<<dfs(0)<<endl;
62     }
63     return 0;
64 }