Submission #337485

#	Time	Username	Problem	Language	Result	Execution time	Memory
337485		tjrwodnjs999	Split the sequence (APIO14_sequence)	C++11	11 / 100	58 ms	85232 KiB

sequence

#include <bits/stdc++.h>
#define ll long long
#define x first
#define y second
using namespace std;
int n,m,arr[100005],pv[100005][205];
ll DP[100005][2],sum[100005];
struct cht{
    int s=0,e=0,num[100005];
    pair<ll,ll> p[100005];
    void clear(){
        s=0,e=0;
    }
    double cross(pair<ll,ll> a,pair<ll,ll> b){
        return 1.0*(a.y-b.y)/(b.x-a.x);
    }
    ll f(ll a,ll b){
        return p[a].x*b+p[a].y;
    }
    pair<ll,ll> qry(ll x){
        while(s+1<e&&f(s,x)<=f(s+1,x)) s++;
        return {f(s,x),num[s]};
    }
    void udt(ll a,ll b,int k){
        p[e]={a,b}; num[e]=k;
        while(s<e&&p[e-1].x==p[e].x&&p[e-1].y<=p[e].y){
            p[e-1]=p[e],num[e-1]=num[e],e--;
        }
        while(s+1<e&&cross(p[e-2],p[e-1])>=cross(p[e-1],p[e])) num[e-1]=num[e],p[e-1]=p[e--];
        e++;
    }
} cht;
int main()
{
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++) scanf("%lld",arr+i),sum[i]=sum[i-1]+arr[i];
    for(int j=1;j<=m;j++){
        cht.clear();
        for(int i=1;i<=n;i++){
            pair<ll,int> qry=cht.qry(sum[i]);
            DP[i][j%2]=qry.x; pv[i][j]=qry.y;
            cht.udt(sum[i],-sum[i]*sum[i]+DP[i][(j+1)%2],i);
        }
    }
    printf("%lld\n",DP[n][m%2]);
    function<void (int,int)> solve =  [&](int a,int b){
        if(b==0) return;
        solve(pv[a][b],b-1);
        printf("%d ",pv[a][b]);
        return;
    };
    solve(n,m);
    return 0;
}

Compilation message (stderr)

sequence.cpp: In member function 'void cht::udt(long long int, long long int, int)':
sequence.cpp:29:90: warning: operation on '((cht*)this)->cht::e' may be undefined [-Wsequence-point]
   29 |         while(s+1<e&&cross(p[e-2],p[e-1])>=cross(p[e-1],p[e])) num[e-1]=num[e],p[e-1]=p[e--];
      |                                                                                         ~^~
sequence.cpp: In function 'int main()':
sequence.cpp:36:37: warning: format '%lld' expects argument of type 'long long int*', but argument 2 has type 'int*' [-Wformat=]
   36 |     for(int i=1;i<=n;i++) scanf("%lld",arr+i),sum[i]=sum[i-1]+arr[i];
      |                                  ~~~^  ~~~~~
      |                                     |     |
      |                                     |     int*
      |                                     long long int*
      |                                  %d
sequence.cpp:35:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   35 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~
sequence.cpp:36:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   36 |     for(int i=1;i<=n;i++) scanf("%lld",arr+i),sum[i]=sum[i-1]+arr[i];
      |                           ~~~~~^~~~~~~~~~~~~~

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