思路

这道题用Py写很方便，因为懒得想dp所以就直接跑暴力过了。

代码

RES=0
maxn=55
dp=[[0 for i in range(maxn)] for j in range(maxn)]
mp=[[0 for i in range(maxn)] for j in range(maxn)]

def dfs(pos,sc,cnt):
    global RES
    if sc<mp[pos][cnt]:
        return
    mp[pos][cnt]=sc
    if cnt==k :
        if RES<sc*dp[pos+1][n-1]:
            RES=sc*dp[pos+1][n-1]
        return
    for i in range(pos+1,n):
        dfs(i,sc*dp[pos+1][i],cnt+1)
    return


n,k=map(int,input().split(' '))
str=input()

for i in range(0,n):
    for j in range(i,n):
        #print(i,j,"!!")
        dp[i][j]=int(str[i:j+1])

for i in range(0,n):
    dfs(i,dp[0][i],1)

print(RES)