为了防止有人抄袭参考我的代码，特意写成这样QWQ勿喷

#include <iostream>
#include <string>
#include <vector>
using namespace std;
vector<int> mul(vector<int> a, vector<int> b) {vector<int> res(a.size() + b.size(), 0);for (int i = 0; i < a.size(); ++i)for (int j = 0; j < b.size(); ++j) {res[i + j] += a[i] * b[j];res[i + j + 1] += res[i + j] / 10;res[i + j] %= 10;}while (res.size() > 1 && res.back() == 0) res.pop_back();return res;}
vector<int> maxv(vector<int> a, vector<int> b) {if (a.size() != b.size()) return a.size() > b.size() ? a : b;for (int i = a.size() - 1; i >= 0; --i)if (a[i] != b[i]) return a[i] > b[i] ? a : b;return a;}
vector<int> numt(const string &s) {vector<int> res;for (int i = s.size() - 1; i >= 0; --i) res.push_back(s[i] - '0');return res;}
int main() {
    int n, k;cin >> n >> k;string s;cin >> s;vector<vector<vector<int>>> dp(k + 2, vector<vector<int>>(n + 2));for (int i = 1; i <= n; ++i) dp[0][i] = numt(s.substr(0, i));for (int m = 1; m <= k; ++m)for (int i = m + 1; i <= n; ++i)for (int j = m; j < i; ++j) {vector<int> t = mul(dp[m - 1][j], numt(s.substr(j, i - j)));if (dp[m][i].empty() || maxv(t, dp[m][i]) == t) dp[m][i] = t;}for (int i = dp[k][n].size() - 1; i >= 0; --i) cout << dp[k][n][i];
    return 0;
}