Submission #130507

#	Time	Username	Problem	Language	Result	Execution time	Memory
130507		fefe	Aliens (IOI16_aliens)	C++17	0 / 100	2 ms	380 KiB

aliens

#include<bits/stdc++.h>
#include "aliens.h"
#define MAX_N 100005
#define fi first
#define se second
#define sq(x) ((x)*(x))
using namespace std;
typedef long long LL;
typedef pair<LL,LL> pil;
struct node{
	LL s,e;
}V[MAX_N];
LL s,e;
LL dp[MAX_N];
pil L[MAX_N];
bool is_ok(pil a,pil b,pil c){
	return (b.se-a.se)*(b.fi-c.fi)<(a.fi-b.fi)*(c.se-b.se);
}
long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c) {	
	LL i;
	for(i=1;i<=n;i++){
		V[i].s=min(r[i-1],c[i-1]);
		V[i].e=max(r[i-1],c[i-1]);
	}
	sort(V+1,V+n+1,[&](const node x,const node y){return (x.s==y.s)?(x.e>y.e):(x.s<y.s);});
	
	m=0;
	LL x=0;
	for(i=1;i<=n;i++){
		if(x<V[i].e)	V[++m]=V[i];
		x=max(x,V[i].e);
	}
	
	n=m;
	sort(V+1,V+n+1,[&](const node x,const node y){return x.e<y.e;});
	
	
	s=e=0;
	L[e++]={-2*V[1].s,sq(V[1].s)-2*V[1].s};
	for(i=1;i<=n;i++){
		while(e-s>1 && L[s].fi*V[i].e+L[s].se>=L[s+1].fi*V[i].e+L[s+1].se)	s++;
		dp[i]=L[s].fi*V[i].e+L[s].se+sq(V[i].e+1);
		pil p={-2*V[i+1].s,sq(V[i+1].s)-2*V[i+1].s+dp[i]};
		if(V[i].e-V[i+1].s+1>0)	p.se+=sq(V[i].e-V[i+1].s+1);
		while(e-s>1 && !is_ok(L[e-2],L[e-1],p))	e--;
		L[e++]=p;
	}
	return dp[n];
}

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