题解

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int mod =  1000000007;


ll dp[201][201];
ll s[201][201];
int main() {
    dp[0][0] = 1ll;
    int n, m, k;
    string a,b;
    cin >> n >> m >> k >> a >> b;
    
    for (int i = 1; i <= n; i++) {
        for (int j = m; j >= 1; j--) {
            for (int l = k; l >= 1; l--) {
                if (a[i - 1] == b[j - 1]) 
                {
                    s[j][l] = s[j - 1][l] + dp[j - 1][l - 1];
                } 
                else 
                {
                    s[j][l] = 0;
                }

                dp[j][l] = (dp[j][l] + s[j][l]) % mod;

            }
        }
    }
    
    cout << dp[m][k];

    return 0;
}