Submission #1209931

#	Time	Username	Problem	Language	Result	Execution time	Memory
1209931		thdh__	Feast (NOI19_feast)	C++17	100 / 100	190 ms	12172 KiB

feast

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define eb emplace_back
#define pu push
#define ins insert
#define fi first
#define se second
#define all(a) a.begin(),a.end()
#define bruh ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fu(x,a,b) for (auto x=a;x<=b;x++)
#define fd(x,a,b) for (auto x=a;x>=b;x--)
#define int ll

using namespace std;
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());

/*
Competitive Programming notes that I need to study & fix my dumbass self:

1. Coding:
- Always be sure to check the memory of arrays (maybe use vectors), for loops, I don't know
- Always try to maximize the memory if possible, even if you are going for subtasks
- Do not exploit #define int long long, it will kill you

2. Stress:
- Don't be cocky and think stressing with your dumbass brute-force solution will give you guaranteed AC. 
- Always try generating big testcases and try if they run

3. Time management:
- Don't overcommit or undercommit, always spend a certain amount of time to think a problem, don't just look at it and say I'm fucked
- Do not spend too much time coding brute-force solutions, they should be easily-codable solutions that don't take up too much time

I hate offline because I am dumb
*/

typedef pair<int, int> ii;
const int N = 3e5+5;
const int mod = 1e9+7;
const int inf = 1e18;
using cd = complex<double>;
const long double PI = acos(-1);
int power(int a,int b) {ll x = 1;if (a >= mod) a%=mod; while (b) {if (b & 1) x = x*a % mod;a = a*a % mod;b>>=1;}return x;} 

int n,k;
int a[N];

ii calc(int lmb) 
{
    ii dp[n][2];
    dp[0][0] = {0,0}, dp[0][1] = {a[0]-lmb, 1};
    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][1].fi + a[i], dp[i-1][1].se), make_pair(dp[i-1][0].fi + a[i] - lmb, dp[i-1][0].se + 1));
    }
    return max(dp[n-1][0], dp[n-1][1]);
}

void solve()
{
	cin>>n>>k;
    for (int i = 0; i < n; i++) cin>>a[i];
    int l = 0, r = 1e18, ans = 0;
    while (l <= r) 
    {
        int mid = l+r>>1;
        if (calc(mid).se <= k) ans = mid, r = mid-1;
        else l = mid+1;
    }
    cout<<calc(ans).fi + ans * k;
}   

/*
Go through the mistakes you usually make and revise your code, for god's sake...
*/

signed main()
{
	bruh
	//freopen("input.inp","r",stdin);
	//freopen("output.inp","w",stdout);
	int t = 1;
	// cin>>t;
	while (t--)
	{
		solve();
		cout<<"\n";
	}
}

• 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