Submission #855398

#	Time	Username	Problem	Language	Result	Execution time	Memory
855398		vjudge1	Split the sequence (APIO14_sequence)	C++17	11 / 100	2090 ms	3928 KiB

sequence

// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

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

#define ordered_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
#define len(x) (int)x.size()
#define ull unsigned long long
#define F first
#define S second
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define int long long
#define double long double
#define pii pair<int,int>

using namespace std;
using namespace __gnu_pbds;
using ll = long long;

const int N = 2e5 + 5;
const int MOD = 1e9 + 7;
const ll INF = 1e18;
const ll inf = 1e9;
int n,k,a[N],mx,p[N],b[N];
int ans[N];

void rec(int idx = 1, int lst = 0){
	if (idx - 1 == k){
		int cur = 0;
		for (int i=1;i<=k;i++){
			cur+=(p[b[i]] - p[b[i-1]]) * (p[n] - p[b[i]]);
		} 
		if (cur >= mx){
			mx = cur;
			for (int i=1;i<=k;i++){
				ans[i] = b[i];	
			}
		}
		return;
	}
	for (int i=lst+1;i<n;i++){
		b[idx] = i;
		rec(idx + 1, i);
	}
}

main(){
	// freopen("sequence.in", "r", stdin);
	// freopen("sequence.out", "w", stdout);
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	cin >> n >> k;
	// b[k+1] = n;
	for (int i=1;i<=n;i++){
		cin >> a[i];
		p[i] = p[i-1] + a[i];
	}
	rec();
	cout << mx << '\n';
	for (int i=1;i<=k;i++){
		cout << ans[i] << ' ';
	}
}

//order_of_key(k): Number of items strictly smaller than k .
//find_by_order(k): K-th element in a set (counting from zero).

//sum of squares n*(n+1)*(2n+1)/6
//sum of cubes [n*(n+1)/2]^2
//sum of squares for odds n*(4*n*n-1)/3
//sum of cubes for odds n*n*(2*n*n-1)

//a/b%mod = a*(b^(m-2)%mod)
//(a>>x)&1 == 0
//a^b = (a+b)-2(a&b)

//srand(time(0))-always changing


// 1 2 3 4 5

Compilation message (stderr)

sequence.cpp:51:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   51 | main(){
      | ^~~~

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