C ++ - Blue Bridge Cup - take the underground palace treasure [2014 Zhenti] [memory search]

Dp began to think that a four-dimensional state have a good job, and then to write a thief nausea

Then change the search, four types of branch want a good, but the complexity is not right?

After giving up, looking solution to a problem, Lv, really two together, memory search.

Well, indeed you, the Blue Bridge Cup, so like violence algorithm!

PS:

Searching for a state, the return value may be 0, so the array assigned to the initial value of -1

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <iostream>
 4 using namespace std;
 5 const int MOD=1e9+7;
 6 int n,m,k;
 7 int v[55][55];
 8 int f[55][55][15][15];
 9 int dfs(int x,int y,int num,int max){
10     if(f[x][y][num][max+1]!=-1)return f[x][y][num][max+1];
11     if(x==n&&y==m)return f[x][y][num][max+1]=(num==k||(num==k-1&&max<v[x][y]));
12     int ans=0;
13     if(x+1<=n){
14         if(max<v[x][y])ans=(ans+dfs(x+1,y,num+1,v[x][y]))%MOD;
15         ans=(ans+dfs(x+1,y,num,max))%MOD;
16     }
17     if(y+1<=m){
18         if(max<v[x][y])ans=(ans+dfs(x,y+1,num+1,v[x][y]))%MOD;
19         ans=(ans+dfs(x,y+1,num,max))%MOD;
20     }
21     return f[x][y][num][max+1]=ans;
22 }
23 int main() {
24     cin>>n>>m>>k;
25     for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)cin>>v[i][j];
26     memset(f,-1,sizeof(f));dfs(1,1,0,-1);
27     cout<<f[1][1][0][0]<<endl;
28     return 0;
29 }