【思维构造】Effects of Anti Pimples—CF1877D

Effects of Anti Pimples—CF1877D

难度大概在1500~1600。
这个D题比C题简单，以后遇到做不出来的题要及时换题。
题目不难，就不写思路了。

$Code$

#include 
#define int long long
#define sz(a) ((int)a.size())
#define all(a) a.begin(), a.end()
using namespace std;
using PII = pair<int, int>;
using i128 = __int128;
const int N = 2e5 + 10;
const int mod = 998244353;

int n;
int a[N], mx[N];

void solve() {
	cin >> n;
	for (int i = 1; i <= n; i ++) cin >> a[i];
	for (int i = 1; i <= n; i ++) {
		int max_a = -1;
		for (int j = i; j <= n; j += i) {
			max_a = max(max_a, a[j]);
		}
		mx[i] = max_a;
	}
	sort(mx + 1, mx + n + 1);
	
	vector<int> power(n + 1);
	power[0] = 1;
	for (int i = 1; i <= n; i ++) {
		power[i] = power[i - 1] * 2 % mod;
	}
	
	int res = 0;
	for (int i = 1; i <= n; i ++) {
		/*
		  res += mx[i] * num;
		  num = 在i - 1个数字中任选x个数字的选法
		  (0 <= x <= i - 1)
		 */
		res = (res + (mx[i] * power[i - 1] % mod)) % mod;
	}
	
	cout << "       ";
	cout << res << "\n";
}

signed main() {
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	int T = 1;
//	cin >> T; cin.get();
	while (T --) solve();
	return 0;
}
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