#pragma GCC optmize(2)
#include<bits/stdc++.h>
using namespace std;
__int128 n,m,a[101],mod = 1000007,f[101][101],maxx,mul;
char ch;
__int128 read(){
	__int128 reg = 1,x = 0;
	char ch = getchar();
	while(ch < '0' || ch > '9'){
		if(ch == '-')reg = -1;
		ch = getchar();
	}
	while(ch >= '0' && ch <= '9'){
		x = x * 10 + (ch - '0');
		ch = getchar();
	}
	return reg * x;
}

void write(__int128 a){
	if(a == 0)return;
	if(a < 0)putchar('-'),a = -a;
	write(a / 10);
	putchar(a % 10 + '0');
}
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	n = read(),m = read();
	f[0][0] = 1;
	for(__int128 i = 1;i <= n;i++)cin >> ch,a[i] = ch - '0';
	for(__int128 i = 1;i <= n;i++){
		mul = 0;
		for(__int128 j = 0;j <= i;j++)mul = mul * 10 + a[j];
		f[i][0] = mul;
		for(__int128 j = 1;j <= m;j++){
			for(__int128 k = j;k < i;k++){
				__int128 mul = 0;
				for(__int128 l = k + 1;l <= i;l++)mul = mul * 10 + a[l];
				f[i][j] = max(f[i][j] , f[k][j - 1] * mul);
			}
		}
	}
	write(f[n][m]);
}

本地运行正确，思路也正确，应该是改成 __int128 后出了问题