Submission #337474

#	Time	Username	Problem	Language	Result	Execution time	Memory
337474		tjrwodnjs999	Split the sequence (APIO14_sequence)	C++11	89 / 100	543 ms	86124 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{
	ll a[101010], b[101010], c[101010];
	int pv, top;

	void clear(){
		pv = top = 0;
	}

	ll f(ll idx, ll x){
		return a[idx]*x + b[idx];
	}

	void udt(ll aa, ll bb, ll cc){
		if(top >= 1 && aa == a[top-1]){
			c[top-1] = cc; return;
		}
		while(top >= 2 && (b[top-1] - b[top-2]) * (a[top-2] - aa) >= (bb - b[top-2]) * (a[top-2] - a[top-1])) top--;
		a[top] = aa;
		b[top] = bb;
		c[top] = cc;
		top++;
		if(pv >= top) pv = top - 1;
	}

	pair<ll,ll> qry(ll x){
		while(pv+1 < top && a[pv+1]*x + b[pv+1] > a[pv]*x + b[pv]) pv++;
		return {f(pv, x), c[pv]};
	}
} 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 function 'int main()':
sequence.cpp:40:37: warning: format '%lld' expects argument of type 'long long int*', but argument 2 has type 'int*' [-Wformat=]
   40 |     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:39:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   39 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~
sequence.cpp:40:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   40 |     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: 0 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 29 / 29