Submission #701729

#	Time	Username	Problem	Language	Result	Execution time	Memory
701729		shmad	Discharging (NOI20_discharging)	C++17	47 / 100	1088 ms	172704 KiB

Discharging

#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 f first
#define s second
#define dbg(x) cerr << #x << " = " << x << '\n'
#define bit(x, i) ((x) >> (i) & 1)

using namespace std;
using ll = long long;
using ld = long double;
using pii = pair<int, int>;

const int N = 1e6 + 5, mod = 1e9 + 7;
const ll inf = 1e18 + 7;
const ld eps = 1e-6;

int n, a[N], dp[N], st[N][20], lg[N];

void build () {
	lg[0] = -1;
	for (int i = 1; i <= n; i++) lg[i] = lg[i / 2] + 1, st[i][0] = a[i];
	for (int j = 1; j <= lg[n]; j++) {
		for (int i = 1; i + (1 << (j - 1)) <= n; i++) st[i][j] = max(st[i][j - 1], st[i + (1 << (j - 1))][j - 1]);
	}
}

int get (int l, int r) {
	int j = lg[r - l + 1];
	return max(st[l][j], st[r - (1 << j) + 1][j]);
}

void solve () {
	cin >> n;
	a[0] = inf;
	bool ok = 1;
	for (int i = 1; i <= n; i++) cin >> a[i], ok &= (a[i] <= a[i - 1]);
	if (ok) cout << a[1] * n << '\n', exit(0);
	build();
	for (int i = 1; i <= n; i++) {
	 	dp[i] = inf;
	 	for (int j = 1; j <= i; j++) dp[i] = min(dp[i], dp[j - 1] + get(j, i) * (n - j + 1));
	}
	cout << dp[n];
	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();
	}
}

• Subtask 1: 9 / 9
• Subtask 2: 13 / 13
• Subtask 3: 0 / 25
• Subtask 4: 11 / 11
• Subtask 5: 14 / 14
• Subtask 6: 0 / 28