Submission #337480

#	Time	Username	Problem	Language	Result	Execution time	Memory
337480		tjrwodnjs999	Split the sequence (APIO14_sequence)	C++11	100 / 100	691 ms	85740 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 lin{
    ll a,b;
};
struct CHT{
    ll s=0,e=0;
    ll idx[101010];
    lin deq[101010];
    double cross(int a, int b) {
        return 1.0 * (deq[a].b - deq[b].b) / (deq[b].a - deq[a].a);
    }
    void udt(lin v,ll lidx){
        deq[e] = v;
        idx[e] = lidx;
        while(s<e&&(deq[e].a==deq[e-1].a)&&deq[e-1].b<=deq[e-1].b){
            deq[e-1] = deq[e];
            idx[e-1] = idx[e];
            e--;
        }
        while(s+1<e && cross(e - 2, e - 1) > cross(e - 1, e)){
            deq[e-1] = deq[e];
            idx[e-1] = idx[e];
            e--;
        }
        e++;
    }
    pair<ll,ll> qry(ll x){
        while(s+1<e && deq[s+1].b - deq[s].b >= x * (deq[s].a - deq[s+1].a))
            s++;
        return {deq[s].a*x+deq[s].b,idx[s]};
    }
    void clear(){
        s=0;
        e=0;
    }

}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(lin, long long int)':
sequence.cpp:21:54: warning: self-comparison always evaluates to true [-Wtautological-compare]
   21 |         while(s<e&&(deq[e].a==deq[e-1].a)&&deq[e-1].b<=deq[e-1].b){
      |                                            ~~~~~~~~~~^~~~~~~~~~~~
sequence.cpp: In function 'int main()':
sequence.cpp:47:37: warning: format '%lld' expects argument of type 'long long int*', but argument 2 has type 'int*' [-Wformat=]
   47 |     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:46:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   46 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~
sequence.cpp:47:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   47 |     for(int i=1;i<=n;i++) scanf("%lld",arr+i),sum[i]=sum[i-1]+arr[i];
      |                           ~~~~~^~~~~~~~~~~~~~

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