Codeforces 163A Substring and Subsequence

http://codeforces.com/problemset/problem/163/A?mobile=true

题目大意：给出两个串，问a的连续子串和b的子串（可以不连续）相同的个数。

思路:在LCS上加点改动

 #include<cstdio>
 #include<cmath>
 #include<cstring>
 #include<algorithm>
 #include<iostream>
 const int Mod=;
 char a[],b[];
 int n,m,f[][];
 int read(){
      int t=,f=;char ch=getchar();
      while (ch<''||ch>''){if (ch=='-') f=-;ch=getchar();}
      while (''<=ch&&ch<=''){t=t*+ch-'';ch=getchar();}
      return t*f;
 }
 int main(){
      scanf("%s",a+);n=strlen(a+);
      scanf("%s",b+);m=strlen(b+);
      for (int i=;i<=n;i++)
         if (a[i]==b[]) f[i][]=;
      for (int i=;i<=m;i++)
         if (a[]==b[i]) f[][i]=;
     int ans=;
     for (int i=;i<=n;i++){
         for (int j=;j<=m;j++){
            f[i][j]=f[i][j-];
            if (a[i]==b[j])
                 (f[i][j]+=f[i-][j-]+)%=Mod;
         }
         ans=(ans+f[i][m])%Mod;
     }
     printf("%d\n",ans);
 }