Submission #1017536

#	Time	Username	Problem	Language	Result	Execution time	Memory
1017536		vjudge1	Feast (NOI19_feast)	C++17	100 / 100	118 ms	15188 KiB

feast

#include<bits/stdc++.h>
using namespace std;
#ifdef ONPC
#include"debug.h"
#else
#define debug(...) 42
#endif
#define endl '\n'
#define ll long long
#define pii pair<int,int>
#define F first
#define S second
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) a.begin(),a.end()
#define int long long
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
const int mod = 1e9 + 7;
const int MAXN = 1e6 + 15;
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3f;
int a[MAXN], n, k;
pair<ll, int> dp[MAXN][2];
pii solve(ll lampda){
	dp[0][1] = {-lampda, 1};
	dp[0][0] = {0, 0};
	for (int i = 1; i <= n; i++){
		dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
		dp[i][1] = max(make_pair(dp[i - 1][0].F + a[i] - lampda, dp[i - 1][0].S + 1), 
				make_pair(dp[i - 1][1].F + a[i], dp[i - 1][1].S));
	}
	return max(dp[n][0], dp[n][1]);
}

int32_t main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> k;
	for (int i = 1; i <= n; i++){
		cin >> a[i];
	}
	ll lo = 0, hi = 1e18;
	while (hi - lo > 1){
		ll mi = (lo + hi) >> 1;
		if (solve(mi).second >= k){
			lo = mi;
		} else {
			hi = mi;
		}
	}
	cout << solve(lo).F + k * lo;
}

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 18 / 18
• Subtask 4: 10 / 10
• Subtask 5: 11 / 11
• Subtask 6: 20 / 20
• Subtask 7: 29 / 29