Submission #588273

#	Time	Username	Problem	Language	Result	Execution time	Memory
588273		sofapuden	Aliens (IOI16_aliens)	C++14	12 / 100	5 ms	364 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll inf = 2e14;
const int mxN = 1e5+5;

struct line{
	ll a, b;
	int cn;
	line(ll _a, ll _b, int _cn) : a(_a), b(_b), cn(_cn) {}
	line(ll _a, ll _b) : line(_a, _b, 0) {}
	ll eval(ll x){return (x-a+1)*(x-a+1)+b;}
};

vector<int> vals;

struct LCT{
	vector<line> st;
	LCT(int n) : st(4*n,line(0,inf)) {}
	void ins(line f, int l, int r, int p){
		if(l > r)return;
		int m = (l+r)>>1;
		bool lf = st[p].eval(vals[l]) > f.eval(vals[l]);
		bool mf = st[p].eval(vals[m]) > f.eval(vals[m]);
		if(mf)swap(st[p],f);
		if(lf == mf)ins(f,m+1,r,p<<1|1);
		else ins(f,l,m-1,p<<1);
	}
	line que(int x, int l, int r, int p){
		int m = (l+r)>>1;
		if(vals[m] == x)return st[p];
		if(vals[m] > x){
			line cu = que(x,l,m-1,p<<1);
			if(st[p].eval(x) < cu.eval(x))return st[p];
			else return cu;
		}
		else{
			line cu = que(x,m+1,r,p<<1|1);
			if(st[p].eval(x) < cu.eval(x))return st[p];
			else return cu;
		}
	}
};

ll take_photos(int N, int M, int k, vector<int> R, vector<int> C) {
	vector<pair<int,int>> v;
	for(int i = 0; i < N; ++i){if(R[i] < C[i])swap(R[i],C[i]);v.push_back({R[i],C[i]});}
	sort(v.begin(),v.end());
	for(int i = 0; i < N; ++i)vals.push_back(v[i].first);


	// dp[n][n][k] current index : start : amount
	// remove k with alien trick
	// remove second n with CHT (LiChaoTree)
	// O(n log^2(n))
	
	ll l = 0, r = inf, ans = 0;
	while(l <= r){
		ll m = (l+r)>>1;
		LCT lct(N);
		lct.ins(line(v[0].second,m,1),0,N-1,1);
		for(int i = 1; i < N; ++i){
			line cu = lct.que(v[i-1].first,0,N-1,1);
			lct.ins(line(v[i].second,m+cu.eval(v[i-1].first)-(v[i-1].first >= v[i].second ? (v[i-1].first-v[i].second+1)*(v[i-1].first-v[i].second) : 0),cu.cn+1),0,N-1,1);
		}
		line cu = lct.que(v[N-1].first,0,N-1,1);
		if(cu.cn > k){
			l = m+1;
		}
		else{
			r = m-1;
			ans = cu.eval(v[N-1].first)-m*k;
		}
	}
    return ans;
}

• Subtask 1: 0 / 4
• Subtask 2: 12 / 12
• Subtask 3: 0 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 40