Submission #633763

#	Time	Username	Problem	Language	Result	Execution time	Memory
633763		shmad	Split the sequence (APIO14_sequence)	C++17	100 / 100	1250 ms	98324 KiB

sequence

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

#include <bits/stdc++.h>

//#define int long long
#define vt vector
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define ff first
#define ss second
#define dbg(x) cerr << #x << " = " << x << '\n'
#define bit(x, i) ((x) >> (i) & 1)

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vvt = vt< vt<int> >;

const int N = 1e6 + 5, mod = 1e9 + 7, B = 500;
const ll inf = 1e18 + 7, LIM = (1ll << 60);
const double eps = 1e-6;

int n, k, pr[N][205];
ll a[N], p[N];
vt<ll> dp(N), dp1(N);

ll cost (int l, int r) {
	return (p[l - 1] * (p[r] - p[l - 1]));
}
 
void merge (int l, int r, int optl, int optr, int lr) {
	if (l > r) return;
	int mid = l + r >> 1;
	ll mn = -inf;
	int opt = -1;
	for (int i = optl; i <= min(optr, mid); i++) {
		ll x = dp[i - 1] + cost(i, mid);
		if (mn <= x) mn = x, opt = i;
	}
	dp1[mid] = mn;
	pr[mid][lr] = opt - 1;
	merge(l, mid - 1, optl, opt, lr);
	merge(mid + 1, r, opt, optr, lr);
}

void solve () {
	cin >> n >> k;
	for (int i = 1; i <= n; i++) cin >> a[i], p[i] = p[i - 1] + a[i];
	for (int i = 1; i <= k; i++) {
		merge(1, n, 1, n, i);
		dp = dp1;
	}
	cout << dp[n] << '\n';
	vt<int> path;
	int cur = n;
	while (k) {
		path.pb(pr[cur][k]);
		cur = pr[cur][k];
		k--;
	}
	reverse(all(path));
	for (int i: path) cout << i << ' ';
	cout << '\n';
}

bool testcases = 0;

signed main() {
#ifdef ONLINE_JUDGE
	freopen(".in", "r", stdin);
	freopen(".out", "w", stdout);
#endif
	cin.tie(0) -> sync_with_stdio(0);
	int test = 1;
	if (testcases) cin >> test;
	for (int cs = 1; cs <= test; cs++) {
		solve();
	}
}

Compilation message (stderr)

sequence.cpp: In function 'void merge(int, int, int, int, int)':
sequence.cpp:35:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   35 |  int mid = l + r >> 1;
      |            ~~^~~

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