Submission #108419

#	Time	Username	Problem	Language	Result	Execution time	Memory
108419		rajarshi_basu	Aliens (IOI16_aliens)	C++14	25 / 100	2037 ms	371604 KiB

aliens

#include <iostream>
#include <vector>
#include <set>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <stdio.h>
#include <cmath>
#include <queue>
#include <string>
#include <map>
#include <complex>
#include <chrono>
#include <random>
#include <stack>
#include <set>
#include <fstream>

#define FOR(i,n) for(int i = 0;i < n; i++)
#define FORE(i,a,b) for(int i = a; i <= b ; i++)
#define ss second
#define ff first
#define ll long long int
#define ii pair<ll,ll>
#define il pair<int,ll>
#define li pair<ll,int>
#define x ff
#define y ss
#define lii pair<ll,pair<int,int> > 
#define piil pair<int ,pair<int,int> > 
#define iii pair<pair<int,int>,int> 
#define pll pair<ll,ll>
#define vi vector<int>
#define pb push_back
#define mp make_pair

#include "aliens.h"

using namespace std;

const ll INF = 1e18;

vector<ii> all;

vector<ii> reduceList(vector<ii> v){
	sort(v.begin(), v.end());
	vector<ii> res;
	ll mx = 0;
	for(auto e:v){

		if(res.empty())res.pb(e);
		else if(res.back().ff < e.ff){
			if(e.ss > mx)res.pb(e);
		}else{
			res.back() = e;
		}
		mx = max(mx,e.ss);
	}
	return res;
}

vector<ii> createRanges(vi r,vi c,int n){
	vector<ii> all;
	FOR(i,n)all.pb({min(r[i],c[i]),max(r[i],c[i])});
	return all;
}

ll C1[50*1000+1];
void prec(){
	C1[0] = 0;	
	FORE(i,1,(int)all.size()-1){
		C1[i] = max((ll)0,all[i-1].ss - all[i].ff+1);
		C1[i] *= C1[i];
	}
}

ll cost(int t,int i){
	i--;
	ll t1 = all[i].ss - all[t].ff + 1; t1*=t1;
	ll t2 = C1[t];
	return t1 - t2;
}

class Segtree{    
    int n;
    struct Node{
        Node* left;
        Node* right;
        pll p;
        Node(){
            left = NULL;
            right = NULL;
            p = {1e9,1e9};
        }
    };

    Node* head;
    inline void expand(Node*& nd){
        if(nd == NULL)nd = new Node();
    }

    inline ll eval(pll p,ll x){
        return p.ff*x+ p.ss;
    }

    inline double intersect(pll p1,pll p2){
        return (p1.ss-p2.ss)*1.0/(p2.ff-p1.ff);
    }

    void update(Node*& node,int ss,int se,pll ln){
        expand(node);
        if(ss == se){
            if(eval(ln,ss) < eval(node->p,ss)){
                node->p = ln;
            }
            return;
        }
        ll v1 = eval(ln,ss);
        ll v2 = eval(ln,se);
        ll v3 = eval(node->p,ss);
        ll v4 = eval(node->p,se);
        if(v1 <= v3 and v2 <= v4){
            node->p = ln;
            return;
        }else if(v3 <= v1 and v4 <= v2){
            return;
        }
        int mid = (ss+se)/2;
        update(node->left,ss,mid,ln);
        update(node->right,mid+1,se,ln);
    }
    ll query(Node* node,int ss,int se,int i){
        if(node == NULL) return INF;
        if(i > se or i < ss)return INF;
        if(ss == se){
            return eval(node->p,i);
        }
        int mid = (ss+se)/2;
        return min(min(eval(node->p,i),query(node->left,ss,mid,i)),query(node->right,mid+1,se,i));
    }

    public : 
    Segtree(){
       
        head = new Node();
    }
    inline void addLine(ll m,ll c){
        update(head,0,1e6+1,{m,c});
    }

    inline ll query(ll x){
        return query(head,0,1e6+1,x);
    }
};

ll dp[50*1000+1][2];
//int opt[50*1000+1][2];
//Segtree ds[50*1000+1];
void computeDp(int k){
	int n = all.size();
	k = min(n,k);
	FOR(i,n+1)dp[i][0] = INF;
	dp[0][0] = 0;
	vector<pll> lns;
	vector<ll> add;
	FOR(i,n){
		add.pb(all[i].ss*all[i].ss + 1 + 2*all[i].ss);
	}
	FOR(j,k+1){
		if(j == 0)continue;
		dp[0][1] = 0;
		
		Segtree ds;
		FORE(t,1,n){
			ds.addLine((-2*all[t-1].ff),(dp[t-1][0] - C1[t-1] + all[t-1].ff*all[t-1].ff - 2*all[t-1].ff));
		}
		for(int i = n;i>=1;i--){
			//ll add = 
			ll mn = ds.query(all[i-1].ss);
			dp[i][1] = mn + add[i-1];
			continue;
		}
		FOR(i,n)dp[i][0] = dp[i][1];//,opt[i][0]= opt[i][1];
	}
}

ll take_photos(int n,int m,int k,vi r,vi c){
	all = reduceList(createRanges(r,c,n));
	prec();
	//for(auto e:all)cout << e.ff<< ";"<<e.ss << endl;
	computeDp(k);/*
	FOR(i,min((int)all.size(),k)+1){
	FOR(j,all.size()+1){
		cout << dp[i][j] << " ";
	};cout << endl;}*/
	return dp[all.size()][1];
	//return 0;
}


/*
int main(){
	//int a[2] = {2,4,4,4,4};
	//int b[2] = {3,5,6,5,6};
	vi a;
	vi b;
	a.pb(1);a.pb(4);
	b.pb(6);b.pb(7);
	cout << take_photos(2,7,2,a,b) << endl;
	return 0;
}

*/

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