Submission #697884

#	Time	Username	Problem	Language	Result	Execution time	Memory
697884		fdnfksd	Split the sequence (APIO14_sequence)	C++17	71 / 100	138 ms	131072 KiB

sequence

#include<bits/stdc++.h>
#define TASKNAME "codeforce"
#define pb push_back
#define pli pair<int,int>
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL);
using namespace std;
using ll=long long;
const ll maxN=1e5+10;
const ll inf=1e18;
const ll mod=1e9+7;
ll n,k,a[maxN],sum=0,pre[maxN],pre2[maxN],dp[maxN][205];
ll cost(ll l,ll r)
{
    return (pre[r]-pre[l-1])*(pre[r]-pre[l-1])-(pre2[r]-pre2[l-1]);
}
ll trace[maxN][205]={0};
void dnc(ll l,ll r,ll optl, ll optr,ll id)
{
    if(l>r) return;
    ll mid=l+r>>1;
    ll opt=0,ans=inf;
    for(int i=optl;i<=min(optr,mid);i++)
    {
        if(dp[i-1][id-1]+cost(i,mid)<ans)
        {
            ans=dp[i-1][id-1]+cost(i,mid);
            opt=i;
        }
    }
    dp[mid][id]=ans;
    trace[mid][id]=opt-1;
    dnc(l,mid-1,optl,opt,id);
    dnc(mid+1,r,opt,optr,id);
}

void solve()
{
    cin >> n >> k;
    k++;
    ll ss=0;
    for(int i=1;i<=n;i++) cin >> a[i],ss+=sum*a[i],sum+=a[i];
    for(int i=1;i<=n;i++)
    {
        pre[i]=pre[i-1]+a[i];
        pre2[i]=pre2[i-1]+a[i]*a[i];
    }
    for(int i=1;i<=n;i++)
    {
        dp[i][1]=pre[i]*pre[i]-pre2[i];
    }
    dp[0][1]=inf;
    for(int j=2;j<=k;j++)
    {
        dnc(j,n,j,n,j);
    }
    cout <<ss-dp[n][k]/2<<'\n';
    ll x=n;
    for(int i=k;i>1;i--)
    {
        cout << trace[x][i]<<' ';
        x=trace[x][i];
    }
}
int main()
{
    fastio
    //freopen(TASKNAME".INP","r",stdin);
    //freopen(TASKNAME".OUT","w",stdout);
    solve();
}

Compilation message (stderr)

sequence.cpp: In function 'void dnc(ll, ll, ll, ll, ll)':
sequence.cpp:20:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   20 |     ll mid=l+r>>1;
      |            ~^~

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