Submission #575404

#	Time	Username	Problem	Language	Result	Execution time	Memory
575404		handlename	Aliens (IOI16_aliens)	C++17	60 / 100	1164 ms	1048576 KiB

aliens

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
const int MOD=1e9+7;
struct convex{
	deque<pair<long long,long long> > dq;
	long long f(pair<long long,long long> line, long long x){
		return line.first*x + line.second;
	}
	long long qry(long long x){
		while(dq.size()>1){
			if(f(dq[0],x)>f(dq[1],x)){ //the next line is better
				dq.pop_front(); //remove useless line
			}
			else break;
		}
		return f(dq[0],x);
	}
	long double intersect(long long m1, long long c1, long long m2, long long c2){
		return (long double)(c2-c1)/(m1-m2);
	}
	long double intersect(pair<long long,long long> p1, pair<long long,long long> p2){
		return intersect(p1.first,p1.second,p2.first,p2.second);
	}
	void ins(long long m,long long c) {//insert line y=mx+c
		pair<long long,long long> line = make_pair(m,c);
		while (dq.size()>1) { //to prevent seg fault
			long long s = dq.size();
			if (intersect(dq[s-1], line) <= intersect(dq[s-2], line)){
				dq.pop_back(); //removes useless line
			}
			else break;
		}
		dq.pb(line);
	}
} *conv;
pair<int,int> brr[200001];
vector<pair<long long,long long> > arr;
long long take_photos(int n,int m,int k,vector<int> r,vector<int> c){
	for (int i=0;i<n;i++){
		r[i]++;
		c[i]++;
		if (r[i]>c[i]) swap(r[i],c[i]); //ri<=ci
		brr[i].first=r[i];
		brr[i].second=c[i];
	}
	sort(brr,brr+n);
	arr.pb(mp(0,0));
	for (int i=0;i<n;i++){
		while (arr.back().first==brr[i].first){
			arr.pop_back();
		}
		if (brr[i].second>arr.back().second){
			arr.pb(brr[i]);
		}
	}
	n=arr.size()-1;
	long long dp[k+1][n+1];
	dp[0][0]=0;
	for (int j=1;j<=n;j++){
		dp[0][j]=1e18;
	}
	for (int i=1;i<=k;i++){
		dp[i][0]=0;
		conv=new convex();
		for (int j=1;j<=n;j++){
			dp[i][j]=1e18;
			long long grad=(1-arr[j].first)*2;
			long long add=dp[i-1][j-1]+(arr[j].first-1)*(arr[j].first-1);
			if (arr[j].first<=arr[j-1].second){
				add-=(arr[j-1].second-arr[j].first+1)*(arr[j-1].second-arr[j].first+1);
			}
			conv->ins(grad,add);
			dp[i][j]=conv->qry(arr[j].second);
			dp[i][j]+=arr[j].second*arr[j].second;
			dp[i][j]=min(dp[i][j],dp[i-1][j]);
		}
	}
	return dp[k][n];
}

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