Submission #898008

#	Time	Username	Problem	Language	Result	Execution time	Memory
898008		JakobZorz	Aliens (IOI16_aliens)	C++17	25 / 100	2072 ms	158736 KiB

aliens

#include"aliens.h"
#include<iostream>
#include<algorithm>
using namespace std;
typedef long long ll;

struct CHT{
    vector<pair<ll,ll>>lines;
    
    void add(pair<ll,ll>line){
        lines.push_back(line);
    }
    
    ll get(ll x){
        ll res=1e18;
        for(auto line:lines){
            res=min(res,line.first*x+line.second);
        }
        return res;
    }
};

int n;
vector<ll>l,r;
ll dp[5000][5000];

ll sq(ll x){
    return x*x;
}

bool cmp(pair<int,int>a,pair<int,int>b){
    if(a.first==b.first)
        return a.second>b.second;
    return a.first<b.first;
}

ll take_photos(int N,int m,int k,vector<int>R,vector<int>C){
    n=N;
    vector<pair<int,int>>intervals_sorted;
    for(int i=0;i<n;i++){
        if(R[i]>C[i])
            swap(R[i],C[i]);
        intervals_sorted.emplace_back(R[i],C[i]);
    }
    sort(intervals_sorted.begin(),intervals_sorted.end(),cmp);
    int right_done=-1;
    for(auto i:intervals_sorted){
        if(i.second>right_done){
            l.push_back(i.first);
            r.push_back(i.second+1);
            right_done=i.second;
        }
    }
    n=(int)l.size();
    
    // cheapest way to cover first i segments with j squares
    for(int i=1;i<=n;i++){
        dp[i][0]=1e12;
    }
    
    for(int j=1;j<=k;j++){
        CHT cht;
        for(int i=0;i<=n;i++){
            dp[i][j]=dp[i][j-1];
            dp[i][j]=min(dp[i][j-1],cht.get(r[i-1])+r[i-1]*r[i-1]);
            if(i!=n){
                pair<ll,ll>el;
                el.first=-2*l[i];
                el.second=l[i]*l[i]+dp[i][j-1];
                if(i&&r[i-1]>l[i]){
                    el.second-=sq(r[i-1]-l[i]);
                }
                cht.add(el);
            }
            /*for(int i2=0;i2<i;i2++){
                ll curr=r[i-1]*r[i-1]-2*l[i2]*r[i-1]+l[i2]*l[i2]+dp[i2][j-1];
                if(i2&&r[i2-1]>l[i2]){
                    curr-=sq(r[i2-1]-l[i2]);
                }
                dp[i][j]=min(dp[i][j],curr);
            }*/
        }
    }
    
    return dp[n][k];
}

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