Submission #23653

#	Time	Username	Problem	Language	Result	Execution time	Memory
23653		SYury	Split the sequence (APIO14_sequence)	C++11	100 / 100	1839 ms	87340 KiB

sequence

#include<bits/stdc++.h>

#pragma GCC optimize("O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx") 

using namespace std;
typedef long long lint;
typedef long double ldb;
typedef unsigned long long uli;

#define X first
#define Y second
#define F(i, l, r) for(auto i = l; i != r; i++)
#define Df(i, l, r) for(auto i = l; i != r; i--)
#define I(i, a) for(auto i : a)
#define pb push_back
#define rs resize
#define mk make_pair
#define asg assign
#define all(x) x.begin(),x.end()
#define ret return
#define cont continue
#define brk break
#define ins insert
#define era erase
#define fi0(x) memset(x, 0, sizeof(x))
#define finf(x) memset(x, 127, sizeof(x))
#define acpy(y, x) memcpy(y, x, sizeof(y))
#define y1 adjf
#define tm dhgdg

const int MAXN = 1e5 + 3;
const int MAXK = 2e2 + 2;
const ldb eps = 1e-16;

int pr[MAXN][MAXK];
int a[MAXN];
int pref[MAXN];
lint sqp[MAXN];
int n, k;
lint lk[2][MAXN];
lint lb[2][MAXN];
int lid[2][MAXN];
int sz[2];
int ptr[2];

lint KEK;

lint f(int ch, int i, int x){
	ret lk[ch][i] * x + lb[ch][i];
}

void add_line(int ch, lint ck, lint cb, int cid){	
		if(sz[ch] > 0 && lk[ch][sz[ch] - 1] == ck && lb[ch][sz[ch] - 1] < cb){sz[ch]--;}
		if(sz[ch] > 0 && lk[ch][sz[ch] - 1] == ck && lb[ch][sz[ch] - 1] >= cb){
			ptr[ch] = min(ptr[ch], sz[ch] - 1);
			ret;
		}
		while(sz[ch] >= 2){
			int p1 = sz[ch] - 1, p2 = sz[ch] - 2;
			ldb f2 = (lb[ch][p2] - lb[ch][p1])/((ldb)lk[ch][p1] - lk[ch][p2]), f1 = (lb[ch][p1] - cb)/((ldb)ck - lk[ch][p1]);
			if(f2 < f1 - eps)brk;
			sz[ch]--;
		}
		lk[ch][sz[ch]] = ck;
		lb[ch][sz[ch]] = cb;	
		lid[ch][sz[ch]] = cid;
		sz[ch]++;
		ptr[ch] = min(ptr[ch], sz[ch] - 1);
}

int get(int ch, int x, int cid){
	if(sz[ch] == 0)ret -1;
	ptr[ch] = min(ptr[ch], sz[ch] - 1);
	while(ptr[ch] < sz[ch] - 1 && lid[ch][ptr[ch] + 1] < cid && f(ch, ptr[ch], x) <= f(ch, ptr[ch] + 1, x))ptr[ch]++;
	if(lid[ch][ptr[ch]] >= cid)ret -1;
	KEK = f(ch, ptr[ch], x);
	ret lid[ch][ptr[ch]];
}

void ch_clear(int ch){
	sz[ch] = 0; ptr[ch] = 0;
}

void restore(int i, int j){
	while(i >= 0){
		printf("%d ", i + 1);
		i = pr[i][j]; j--;
	}
}

lint dcp[MAXN];

int main(){
//	freopen("input.txt", "r", stdin);
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	scanf("%d%d", &n, &k);
	F(i, 0, n)scanf("%d", &a[i]);
	F(i, 0, n)pref[i] = a[i] + ((i == 0) ? 0 : pref[i - 1]);
	k++;
	F(i, 0, n)sqp[i] = pref[i] * 1ll * pref[i];
	F(i, 0, n)
		F(j, 1, k + 1)
			pr[i][j] = -2;
	F(i, 0, n)pr[i][1] = -1;
	F(i, 0, n)add_line(0, pref[i], -sqp[i], i);
	int tc = 1;
	F(j, 2, k + 1){
		ch_clear(tc);
		F(i, j - 1, n){
			int tmp = get(1 - tc, pref[i], i);
			if(tmp == -1){cont;}
			dcp[i] = KEK;
			pr[i][j] = tmp;
			add_line(tc, pref[i], dcp[i] - sqp[i], i);
		}
		tc = 1 - tc;
	}
	printf("%lld\n", dcp[n - 1]);
	restore(pr[n - 1][k], k - 1);
	ret 0;
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:98:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &k);
                       ^
sequence.cpp:99:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  F(i, 0, n)scanf("%d", &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