CodeForces-981D Bookshelves

传送门：CoderForces - 981D

思路分析

按位进行贪心，每一位进行dp，要满足之前所产生的答案，dp[i][j]表示前i个能否分成j组

AC代码

#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define pb push_back
#define mp make_pair
#define fun function
#define sz(x) (x).size()
#define lowbit(x) (x)&(-x)
#define all(x) (x).begin(),(x).end()
#define mem(a,b) memset(a,b,sizeof(a))

namespace FastIO {
#define BUF_SIZE 100000
#define OUT_SIZE 100000
    bool IOerror=0;
    inline char nc() {
        static char buf[BUF_SIZE],*p1=buf+BUF_SIZE,*pend=buf+BUF_SIZE;
        if(p1==pend) {
            p1=buf;
            pend=buf+fread(buf,1,BUF_SIZE,stdin);
            if(pend==p1) {
                IOerror=1;
                return -1;
            }
        }
        return *p1++;
    }
    inline bool blank(char ch) {
        return ch==' '||ch=='\n'||ch=='\r'||ch=='\t';
    }
    template<class T> inline bool read(T &x) {
        bool sign=0;
        char ch=nc();
        x=0;
        for(; blank(ch); ch=nc());
        if(IOerror)return false;
        if(ch=='-')sign=1,ch=nc();
        for(; ch>='0'&&ch<='9'; ch=nc())x=x*10+ch-'0';
        if(sign)x=-x;
        return true;
    }
    template<class T,class... U>bool read(T& h,U&... t) {
        return read(h)&&read(t...);
    }
#undef OUT_SIZE
#undef BUF_SIZE
};
using namespace std;
using namespace FastIO;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int INF = 0x3f3f3f3f;
#define int long long
int dp[55][55],s[55];
int n,m,ans;

int solve(int x) {
    mem(dp,0);
    int now=(ans|(1LL<<x));
    dp[0][0]=1;
    for(int i=1; i<=n; i++) {
        for(int j=0; j<i; j++) {
            for(int k=1; k<=i; k++) {
                int sum=s[i]-s[j];
                if((sum&now)>=now) dp[i][k]|=dp[j][k-1];
            }
        }
    }
    return dp[n][m];
}


signed main() {

#ifdef xiaofan
    freopen("1.in","r",stdin);
    freopen("1.out","w",stdout);
#endif

    cin>>n>>m;
    for(int i=1; i<=n; i++) {
        int x;
        cin>>x;
        s[i]=s[i-1]+x;
    }
    for(int i=61; i>=0; i--) if(solve(i)) ans|=(1LL<<i);
    cout<<ans<<endl;





    return 0;
}