Submission #717086

#	Time	Username	Problem	Language	Result	Execution time	Memory
717086		pragmatist	Split the sequence (APIO14_sequence)	C++17	100 / 100	1467 ms	81740 KiB

sequence

#include <bits/stdc++.h>                     
  
#define ll long long 
#define pb push_back
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define sz(v) (int)v.size()
#define x first
#define y second
#define nl "\n"
  
using namespace std;
  
const int N = (int)1e5 + 7;
const int M = (int)2e6 + 5e5 + 7;
const ll MOD = (ll)1e9;                    
const int inf = (int)1e9 + 7;
const int B = (int)390;
const ll INF = (ll)1e18 + 7;
  
pair<int, int> dir[] = {{-1, 0}, {1, 0}, {0, 1}, {0, -1}};
 
bool bit(int mask, int i) {
    return (mask >> i & 1);
}
  
int sum(int x, int y) {
    x += y;
    if(x >= MOD) x -= MOD;
    return x;
}
  
int mult(int x, int y) {
    return 1ll * x * y % MOD;
}

int n, k, cr, a[N], p[N][201];
ll dp[2][N], suf[N];

void calc(int l, int r, int tl, int tr) {
    if(l > r)
        return;
    int mid = (l + r) >> 1, x = l;
    dp[1][mid] = -INF;
    for(int i = tl; i <= min(mid, tr); ++i) {
        ll cur = dp[0][i - 1] + (suf[i] - suf[mid + 1]) * suf[mid + 1];
        if(cur > dp[1][mid]) {
            dp[1][mid] = cur;
            p[mid][cr] = i - 1;
            x = i;
        }
    }
    calc(l, mid - 1, tl, x);
    calc(mid + 1, r, x, tr);
}

void solve() {
	cin >> n >> k;
	for(int i = 1; i <= n; ++i) cin >> a[i];
	for(int i = n; i >= 1; --i) suf[i] = suf[i + 1] + a[i];
	ll ans = -INF;                                                          
	int lst = -1;
	for(int i = 0; i < 2; ++i) {
		for(int j = 0; j <= n; ++j) {
			dp[i][j] = -INF;
		}
	}
	dp[0][0] = 0;
	for(int i = 1; i <= k; ++i) {
	    cr = i;
	    calc(1, n, 1, n);
	    if(i == k) {
	        for(int j = 1; j <= n; ++j) {
	            if(dp[1][j] > ans) {
	                ans = dp[1][j];
	                lst = j;
	            }
	        }
	    }
	    for(int j = 0; j <= n; ++j) {
	        dp[0][j] = dp[1][j];
	    }
	}
	assert(lst != -1);
	vector<int> v;
	while(lst > 0) {
		v.pb(lst);
		lst = p[lst][k--];
	} 
	reverse(all(v));
	cout << ans << nl;
	for(auto x : v) cout << x << ' ';
}       
 
  
signed main() {                   
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    //freopen("sequence.in", "r", stdin);
    //freopen("sequence.out", "w", stdout);     
    int test = 1;                       
    //cin >> test;
    for(int i = 1; i <= test; ++i) {
        //cout << "Case " << i << ":\n";
        solve();
    }
    return 0;
}                   
/*
possible causes of error :
* array  bounds
* int overflow
* special case (n == 1?)
* haven't clean something
* wrong N | M | inf | INF | MOD

* try to write brute force to find test
* don't waste time
* don't write bullshit
* solution is easy
*/

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