Submission #127026

#	Time	Username	Problem	Language	Result	Execution time	Memory
127026		liwi	Split the sequence (APIO14_sequence)	C++11	100 / 100	1244 ms	84244 KiB

sequence

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;

#define scan(x) do{while((x=getchar())<'0'); for(x-='0'; '0'<=(_=getchar()); x=(x<<3)+(x<<1)+_-'0');}while(0)
char _;
#define complete_unique(a) a.erase(unique(a.begin(),a.end()),a.end())
#define all(a) a.begin(),a.end()
#define println printf("\n");
#define readln(x) getline(cin,x);
#define pb push_back
#define endl "\n"
#define INT_INF 0x3f3f3f3f
#define LL_INF 0x3f3f3f3f3f3f3f3f
#define MOD 1000000007
#define mp make_pair
#define fastio cin.tie(0); cin.sync_with_stdio(0);

#define MAXN 100005
#define MAXK 205

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
typedef unordered_map<int,int> umii;
typedef pair<int,int> pii;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef pair<int,pii> triple;
typedef int8_t byte;

mt19937 g1(time(0));

int randint(int a, int b){return uniform_int_distribution<int>(a, b)(g1);}
ll randlong(ll a,ll b){return uniform_int_distribution<long long>(a, b)(g1);}

ll gcd(ll a, ll b){return b == 0 ? a : gcd(b, a % b);}
ll lcm(ll a, ll b){return a*b/gcd(a,b);}
ll fpow(ll  b, ll exp, ll mod){if(exp == 0) return 1;ll t = fpow(b,exp/2,mod);if(exp&1) return t*t%mod*b%mod;return t*t%mod;}
ll divmod(ll i, ll j, ll mod){i%=mod,j%=mod;return i*fpow(j,mod-2,mod)%mod;}

int len,K,arr[MAXN],par[MAXN][MAXK],dq[MAXN],l,r,lst;
ll dp[MAXN][2],psa[MAXN];

inline double inter(int a, int b, int k){
	double m1 = psa[a], b1 = -(psa[a]*psa[a])+dp[a][!k];
	double m2 = psa[b], b2 = -(psa[b]*psa[b])+dp[b][!k];
	double x = (b2-b1)/(m1-m2);
	return x;
}

int main(){
	scanf("%d %d",&len,&K); K++;
	for(int i=1; i<=len; i++){
		scanf(" %d",&arr[i]);
		psa[i] = psa[i-1]+arr[i];
	}
	for(int k=2; k<=K; k++){
		lst = !lst;
		l = r = 0;
		dq[l] = 0;
		for(int i=1; i<=len; i++){
			while(r-l+1 >= 2 && dp[dq[l+1]][!lst]+(psa[i]-psa[dq[l+1]])*psa[dq[l+1]] >= dp[dq[l]][!lst]+(psa[i]-psa[dq[l]])*psa[dq[l]])
				l++;
			dp[i][lst] = dp[dq[l]][!lst]+(psa[i]-psa[dq[l]])*psa[dq[l]];
			par[i][k] = dq[l];
			while(r-l+1 >= 2 && inter(dq[r-1],i,lst) <= inter(dq[r-1],dq[r],lst))
				r--;
			dq[++r] = i;
		}
	}
	printf("%lld\n",dp[len][lst]);
	vector<int> v;
	int curr = len;
	for(int i=K; i>=1; i--){
		if(i < K) v.pb(curr);
		curr = par[curr][i];
	}
	for(int i=(int)v.size()-1; i>=0; i--)
		printf("%d ",v[i]);
}
/*
4 1
0 0 1 1
ans=1
 */

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:57:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&len,&K); K++;
  ~~~~~^~~~~~~~~~~~~~~~~
sequence.cpp:59:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf(" %d",&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