Submission #41997

#	Time	Username	Problem	Language	Result	Execution time	Memory
41997		Aidyn_A	Split the sequence (APIO14_sequence)	C++14	39 / 100	197 ms	104548 KiB

sequence

#include <stdio.h>
#include <bits/stdc++.h>			

#define pb push_back
#define pf push_front
#define pp pop_back
#define sz(a) (int)(a.size())
#define mp make_pair
#define F first
#define S second
#define next _next
#define prev _prev
#define left _left
#define right _right
#define y1 _y1
#define all(x) x.begin(), x.end()
#define what_is(x) #x << " is " << (x)

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int N = (int)1e5 + 2;
const ll INF = (ll)1e18 + 123;
const int inf = (int)1e9 + 123;
const int MOD = (int)1e9 + 7;

void megaRandom() {
	unsigned int FOR;
 	asm("rdtsc" : "=A"(FOR));
  srand(FOR);
}

struct line {
	ld k, b;
	int ind;
	line() {
		k = b = 0;
		ind = 0;
	}
};
                                 
ld intersection(line a, line z) {
	//if(a.k == z.k)
		//return 0;
	return (z.b - a.b) / (a.k - z.k);
}

vector<line> what;

void add(line a) {
	while(sz(what) > 0 && what.back().k == a.k && what.back().b <= a.b)
		what.pp();
	while(sz(what) > 1 && intersection(what[sz(what) - 2], a) <= intersection(what[sz(what) - 2], what.back()))
		what.pp();
	what.pb(a);
}

int n, k;
int a[N];
ll now[N], prev[N];
int pref[N];
int pr[202][N];

int main() {
	megaRandom();
	cin >> n >> k;
	k ++;
	for(int i = 1; i <= n; i ++) {
		cin >> a[i];
		pref[i] = pref[i - 1] + a[i];
	}
	prev[0] = 0;
	for(int it = 1; it <= k; it ++) {
		memset(now, 0, sizeof now);		
		what.clear();
		int jt = 0;
		if(it > 1) { 
			for(int i = 1; i <= n; i ++) {
				ll val = 0;
				while(jt + 1 < sz(what) && intersection(what[jt], what[jt + 1]) < pref[i])
					jt ++;
				int j = -1;
				if(jt < sz(what)) 
					j = what[jt].ind;
				else 
					j = 0; //cout << "UNEXPECTED TURN!!!\n"; //return 0;
				
				assert(j <= i);			
				now[i] = prev[j] + 1ll * pref[j] * (pref[i] - pref[j]);
				pr[it][i] = j;
				//cout << "it: " << it << " i: " << i << " j: " << j << "\n";
				
				line cur = *new line();
				
				cur.k = pref[i];
				cur.b = prev[i] - (1ll * pref[i] * pref[i]);
				cur.ind = i;
				add(cur);
			}
		}
		for(int i = 1; i <= n; i ++) 
			prev[i] = now[i];
	}
	cout << prev[n] << "\n";
	int x = k, y = n;
	vector<int> g;
	while(x > 1) {
		g.pb(pr[x][y]);
		y = pr[x][y], x --;
	}
	reverse(all(g));
	for(int i = 0; i < sz(g); i ++) 
		cout << g[i] << ' ';
	return 0;  
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:84:8: warning: unused variable 'val' [-Wunused-variable]
     ll val = 0;
        ^

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