bzoj 1566: [NOI2009]管道取珠

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<algorithm>
 4 #define N 100005
 5 using namespace std;
 6 int n,m,f[505][505][505];
 7 char a[1005],b[1005];
 8 const int mod=1024523;
 9 void add(int &x, int y)
10 {
11     x+=y; x%=mod;
12 }
13 int main()
14 {
15     scanf("%d%d",&n,&m);
16     scanf("%s",a+1); scanf("%s",b+1);
17     reverse(a+1,a+n+1); reverse(b+1,b+m+1);
18     f[0][0][0]=1;
19     for (int i=0; i<=n; i++)
20         for (int j=0; j<=m; j++)
21             for (int k=0; k<=n; k++)
22             {
23                 int l=i+j-k,t=f[i][j][k];
24                 if (l<0 || l>m) continue;
25                 if (a[i+1]==a[k+1]) add(f[i+1][j][k+1],t);
26                 if (a[i+1]==b[l+1]) add(f[i+1][j][k],t);
27                 if (b[j+1]==a[k+1]) add(f[i][j+1][k+1],t);
28                 if (b[j+1]==b[l+1]) add(f[i][j+1][k],t);
29             }
30     cout<<f[n][m][n];
31     return 0;
32 }