Submission #990086

#	Time	Username	Problem	Language	Result	Execution time	Memory
990086		StefanSebez	Split the sequence (APIO14_sequence)	C++14	100 / 100	640 ms	82264 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define ll long long
const int N=1e5+10;
const ll inf=1e18;
int n,K,a[N];
ll dp[N][2],pref[N];
int parent[N][201];
/*int root,nc,lc[2*N],rc[2*N],sum[2*N],sum1[2*N],lazy[2*N];

void pull(int c){
	sum1[c]=sum1[lc[c]]+sum1[rc[c]];
	sum[c]=sum[lc[c]]+sum[rc[c]]+sum1[c]*sum1[c]-sum1[lc[c]]*sum1[lc[c]]-sum1[rc[c]]*sum1[rc[c]];
}
void update(int c,int qval){
	sum[c]+=qval*qval+2*sum1[c]*qval;
	sum1[c]+=qval;
	lazy[c]+=qval;
}
void push(int c){
	update(lc[c],lazy[c]);
	update(rc[c],lazy[c]);
	lazy[c]=0;
}
void Build(int &c,int ss,int se,int k){
	if(!c) c=++nc;
	sum[c]=sum1[c]=lazy[c]=0;
	if(ss==se){
		sum[c]=dp[ss][k];
		return;
	}
	int mid=ss+se>>1;
	Build(lc[c],ss,mid,k),Build(rc[c],mid+1,se,k);
	pull(c);
}
void Update(int &c,int ss,int se,int qs,int qe,int qval){
	if(qs>qe) return;
	if(qs<=ss && se<=qe){
		update(c,qval);
		return;
	}
	if(qe<ss || se<qs) return;
	int mid=ss+se>>1;
	push(c);
	Update(lc[c],ss,mid,qs,qe,qval),Update(rc[c],mid+1,se,qs,qe,qval);
	pull(c);
}
int Get(int c,int ss,int se,int qs,int qe){
	if(qs>qe) return inf;
	if(qs<=ss && se<=qe) return sum[c];
	if(qe<ss || se<qs) return inf;
	int mid=ss+se>>1;
	push(c);
	return min(Get(lc[c],ss,mid,qs,qe),Get(rc[c],mid+1,se,qs,qe));
}*/
ll Cost(int l,int r){return (pref[r]-pref[l-1])*(pref[r]-pref[l-1]);}
void Solve(int l,int r,int L,int R,int k){
	if(l>r) return;
	int mid=l+r>>1;
	int ind=L;
	dp[mid][0]=inf;
	for(int i=min(mid-1,R);i>=L;i--){
		if(dp[mid][0]>=dp[i][1]+Cost(i+1,mid)){
			dp[mid][0]=dp[i][1]+Cost(i+1,mid);
			ind=i;
		}
	}
	parent[mid][k]=ind;
	Solve(l,mid-1,L,ind,k);
	Solve(mid+1,r,ind,R,k);
}
int main(){
    scanf("%i%i",&n,&K);
    for(int i=1;i<=n;i++) scanf("%i",&a[i]);
    for(int i=1;i<=n;i++) pref[i]=pref[i-1]+a[i];
    for(ll i=0,sum=0;i<=n;i++) sum+=a[i],dp[i][1]=sum*sum;
	/*for(int k=1;k<=K;k++){
		Build(root,0,n,k-1);
		dp[0][k]=inf;
		for(int i=0;i<=n;i++) printf("%i ",Get(root,0,n,i,i));
		printf("\n");
		for(int i=1;i<=n;i++){
			Update(root,0,n,0,i-1,a[i]);
			dp[i][k]=Get(root,0,n,0,i-1);
			for(int i=0;i<=n;i++) printf("%i ",Get(root,0,n,i,i));
			printf("\n");
			//for(int j=i-1,sum=0;j>=0;j--){
				//sum+=a[j+1];
				//dp[i][k]=min(dp[i][k],dp[j][k-1]+sum*sum);
			//}
		}
		printf("\n");
	}
	for(int k=0;k<=K;k++){printf("%i: ",k);for(int i=0;i<=n;i++){printf("%i ",dp[i][k]);}printf("\n");}*/
	for(int k=1;k<=K;k++){
		Solve(1,n,1,n,k);
		for(int i=1;i<=n;i++) dp[i][1]=dp[i][0];
	}
	ll res=0;
	for(int i=1;i<=n;i++) res+=a[i];
	res=(res*res-dp[n][0])/2;
	printf("%lld\n",res);
	vector<int>ans;
	int temp=K,nesto=n;
	while(temp>0){
		ans.pb(parent[nesto][temp]);
		nesto=parent[nesto][temp];
		temp--;
	}
	for(auto i:ans) printf("%i ",i);
	printf("\n");
    return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'void Solve(int, int, int, int, int)':
sequence.cpp:62:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   62 |  int mid=l+r>>1;
      |          ~^~
sequence.cpp: In function 'int main()':
sequence.cpp:76:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |     scanf("%i%i",&n,&K);
      |     ~~~~~^~~~~~~~~~~~~~
sequence.cpp:77:32: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |     for(int i=1;i<=n;i++) scanf("%i",&a[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