【Luogu】P2389电脑班的裁员（DP）

#include<cstdio>
#include<cstdlib>
#include<cctype>
#include<algorithm>
#include<cstring>
#define maxn 550
using namespace std;

inline long long read(){
    long long num=0,f=1;
    char ch=getchar();
    while(!isdigit(ch)){
        if(ch==‘-‘)    f=-1;
        ch=getchar();
    }
    while(isdigit(ch)){
        num=num*10+ch-‘0‘;     
        ch=getchar();
    }
    return num*f;
}

long long f[maxn][maxn];
long long ans;
long long sum[maxn];

int main(){
    int n=read(),m=read();
    for(int i=1;i<=n;++i)    sum[i]=sum[i-1]+read();
    memset(f,-127/3,sizeof(f));
    ans=0;    f[0][0]=0;
    for(int i=1;i<=n;++i){
        f[i][0]=0;
        for(int j=1;j<=i&&j<=m;++j){
            f[i][j]=max(f[i][j],f[i-1][j]);
            for(int k=0;k<i;++k){
                f[i][j]=max(f[i][j],f[k][j-1]+sum[i]-sum[k]);
                ans=max(ans,f[i][j]);
            }
        }
    }
    printf("%lld\n",ans);
    return 0;
}