大佬们帮一下呗

#include<iostream>
#include<cstring>
#include<string>
#include<cstdio>
using namespace std;
const int maxN=1010;
const int maxM=210;
const int maxK=210;
const long long mod=1000000007;
int n,m,k;
int ne,now;
string s1,s2;
int f[2][maxM][maxK],g[2][maxM][maxK];

void prepare()
{
	if(s1[0]==s2[0]){
		f[now][1][1]=1;
		g[now][1][1]=1;
	}
	for(int i=2;i<=n;++i){
		ne=1-now;
		f[ne][0][0]=1;
		for(int j=1;j<=i;++j){
			for(int l=1;l<=min(k,j);++l){
				if(s1[i-1]==s2[j-1]){
					g[ne][j][l]=(f[now][j-1][l-1]+g[now][j-1][l])%mod;
					f[ne][j][l]=((f[now][j][l]+f[now][j-1][l-1])%mod+g[now][j-1][l])%mod;
				}
				else{
					g[ne][j][l]=0;
					f[ne][j][l]=f[now][j][l];
				}
				cout<<i<<" "<<j<<" "<<l<<" "<<f[ne][j][l]<<" "<<g[ne][j][l]<<endl;
			}
		}
	}
}

int main()
{
	//freopen("substring.in","r",stdin);
	//freopen("substring.out","w",stdout);
	cin>>n>>m>>k;
	cin>>s1>>s2;
	prepare();
	cout<<f[ne][m][k]%mod<<endl;
	return 0;
}