Submission #989709

#	Time	Username	Problem	Language	Result	Execution time	Memory
989709		kustizus	Split the sequence (APIO14_sequence)	C++17	0 / 100	50 ms	131072 KiB

sequence

#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N=1e5;
int n,k,idx=1,a[N+5],pre[N+5],bef1[N+5][205];
vector <int> bef(N+5),dp(N+5);
int Cal(int i, int j){
    return (pre[j]-pre[i-1])*(pre[n]-pre[j]);
}
void dnc(int l, int r, int optl, int optr){
    if (l>r) return;
    int md=l+r>>1,ans=-1e18,pos=0;
    for (int i=min(optr,md);i>=optl;--i){
        int d=bef[i-1]+Cal(i,md);
        if (d>ans){
            ans=d;
            pos=i;
        }
    }
    dp[md]=ans;
    bef1[md][idx]=pos;
    dnc(l,md-1,optl,pos);
    dnc(md+1,r,pos,optr);
}
void Solve(){
    cin>>n>>k;
    for (int i=1;i<=n;++i){
        cin>>a[i];
        pre[i]=pre[i-1]+a[i];
    }
    for (int i=1;i<=n;++i) bef[i]=Cal(1,i);
    for (int i=2;i<=k;++i){
        ++idx;
        dnc(i,n,i,n);
        for (int j=1;j<=n;++j){
            bef[j]=dp[j];
            dp[j]=0;
        }
    }
    int ans=-1e18,pos;
    for (int i=1;i<=n;++i)
        if (bef[i]>ans){
            ans=bef[i];
            pos=i;
        }
    cout<<ans<<"\n";
    for (int i=k;i>=1;--i){
        cout<<pos<<' ';
        if (bef1[pos][i]-1<0 || bef1[pos][i]-1>n){
            cout<<1<<' ';
            continue;
        }
        pos=bef1[pos][i]-1;
    }
}
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    // freopen ("FILE.INP","r",stdin);
    // freopen ("FILE.OUT","w",stdout);
    int t=1;
    // cin>>t;
    while (t--) Solve();
}

Compilation message (stderr)

sequence.cpp: In function 'void dnc(long long int, long long int, long long int, long long int)':
sequence.cpp:12:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   12 |     int md=l+r>>1,ans=-1e18,pos=0;
      |            ~^~
sequence.cpp: In function 'void Solve()':
sequence.cpp:49:24: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   49 |         if (bef1[pos][i]-1<0 || bef1[pos][i]-1>n){
      |             ~~~~~~~~~~~^

• Subtask 1: 0 / 11
• Subtask 2: 0 / 11
• Subtask 3: 0 / 11
• Subtask 4: 0 / 17
• Subtask 5: 0 / 21
• Subtask 6: 0 / 29