Submission #1255682

#	Time	Username	Problem	Language	Result	Execution time	Memory
1255682		thdh__	Cake 3 (JOI19_cake3)	C++20	100 / 100	895 ms	141716 KiB

cake3

#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;
//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
- 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: 
- 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

Time management schedule:
Offline / LAH days (4 problems - 3h):
15' thinking of solution / idea
1. no idea: skip
2. yes idea: continue thinking for <= 15'

+ implementing: <= 20'
+ brute-force: <= 5'
+ test generator: <= 5'

I hate offline because I am dumb
*/

typedef pair<int, int> ii;
const int N = 2e5+5;
const int B = 750;
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;} 

struct node {
	int l = -1, r = -1, cnt = 0, sum = 0;
	node(){}
	node(int l, int r, int cnt, int sum): l(l), r(r), cnt(cnt), sum(sum) {}
};

int n,m, ans = -inf;
vector<ii> a;
vector<int> v;

vector<node> st;
int ver[N];

int build(int l, int r) 
{
	if (l == r) 
	{
		st.pb(node());
		return st.size()-1;
	}
	int mid = l+r>>1;
	node cur = node();
	cur.l = build(l, mid), cur.r = build(mid+1, r);
	st.pb(cur);
	return st.size()-1;
}

int update(int oldid, int l, int r, int i) 
{
	if (l == r) 
	{
		st.pb(node(-1, -1, st[oldid].cnt+1, st[oldid].sum+v[l]));
		return st.size()-1;
	}
	int mid = l+r>>1;
	node cur = node();
	if (i <= mid) 
	{
		cur.l = update(st[oldid].l, l, mid, i);
		cur.r = st[oldid].r;
	} else 
	{
		cur.l = st[oldid].l;
		cur.r = update(st[oldid].r, mid+1, r, i);
	}
	cur.cnt = st[cur.l].cnt + st[cur.r].cnt;
	cur.sum = st[cur.l].sum + st[cur.r].sum;
	st.pb(cur);
	return st.size()-1;
}

int walk(int oldid, int id, int l, int r, int k) 
{
	if (l == r) 
	{
		return min(k, st[id].cnt - st[oldid].cnt) * v[l];
	}
	int mid = l+r>>1;
	if (st[st[id].r].cnt - st[st[oldid].r].cnt >= k) return walk(st[oldid].r, st[id].r, mid+1, r, k);
	return (st[st[id].r].sum - st[st[oldid].r].sum) + walk(st[oldid].l, st[id].l, l, mid, k-(st[st[id].r].cnt - st[st[oldid].r].cnt));
}

void dnc(int l, int r, int optl, int optr) 
{
	if (l > r) return;
	int mid = l+r>>1;
	ii best = {-inf, -1};
	for (int i = optl; i <= min(optr, mid-m+1); i++) 
	{
		int val = walk(ver[i-1], ver[mid], 0, v.size()-1, m) - 2ll * (a[mid].fi - a[i].fi);
		// cout<<i<<" "<<mid<<" "<<val<<" "<<2 * (a[mid].fi - a[i].fi)<<endl;
		best = max(best, {val, i});
	}
	// cout<<mid<<" "<<best.se<<" "<<best.fi<<endl;
	// cout<<l<<" "<<r<<" "<<best.fi<<endl;
	ans = max(ans, best.fi);
	dnc(l, mid-1, optl, best.se); dnc(mid+1, r, best.se, optr);
}

void solve()
{
	cin>>n>>m;
	a.pb({0, 0});
	for (int i = 1; i <= n; i++) 
	{
		int x,y;
		cin>>x>>y;
		a.pb({y, x});
		v.pb(x);
	}
	sort(all(v)); v.erase(unique(all(v)), v.end());
	for (int i = 1; i <= n; i++) a[i].se = lower_bound(all(v), a[i].se) - v.begin();
	sort(all(a));
	// for (int i = 1; i <= n; i++) cout<<a[i].fi<<" "<<v[a[i].se]<<endl;
	ver[0] = build(0,v.size()-1);
	for (int i = 1; i <= n; i++) 
	{
		ver[i] = update(ver[i-1], 0, v.size()-1, a[i].se);
	}
	dnc(m, n, 1, n-m+1);
	cout<<ans;
}

/*
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: 5 / 5
• Subtask 2: 19 / 19
• Subtask 3: 76 / 76