Submission #170275

#	Time	Username	Problem	Language	Result	Execution time	Memory
170275		dennisstar	Aliens (IOI16_aliens)	C++11	4 / 100	2 ms	764 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>
#define fi first
#define se second
#define ryan bear
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef long double ld;
typedef vector<int> vim;
typedef vector<ll> vlm;

int n, m;

pii im[100010]; vim chk(100010);
vector<pll> ar;

ll sq(ll i) {return i*i;}
pll stk[100010]; ll cnt[100010]; int fr, tp;

ll lin(ll i, ll x) { return stk[i].fi*x+stk[i].se;}
pll cal(ll x) {
	while (fr<tp-1 && lin(fr, x)>=lin(fr+1, x)) fr++;
	return {lin(fr, x), cnt[fr]};
}

void add(ll a, ll b, ll c) {
	while (fr<tp-1 && (stk[tp-1].fi-a)*(stk[tp-2].se-stk[tp-1].se) <= (stk[tp-2].fi-stk[tp-1].fi)*(stk[tp-2].se-b)) tp--;
	stk[tp]={a, b};
	cnt[tp++]=c;
}

pll f(ll cost) {
	fr=tp=0;

	vlm Dp(n+1), c(n+1);
	add(-2*(ar[1].se-1), sq(ar[1].se-1)+cost, 1);
	Dp[1]=cal(ar[1].fi).fi+sq(ar[1].fi);
	c[1]=1;

	pll pl;
	
	for (int i=2; i<=n; i++) {
		add(-2*(ar[i].se-1), sq(ar[i].se-1)-sq( max(0ll, (ar[i-1].fi-ar[i].se+1)) )+Dp[i-1]+cost, c[i-1]+1);
		pl=cal(ar[i].fi);
		Dp[i]=sq(ar[i].fi)+pl.fi, c[i]=pl.se; 
	}
	return {c[n], Dp[n]-c[n]*cost};
}

ll take_photos(int n_, int m_, int k, vim r, vim c) { //(r-c+1)^2
	n=n_; m=m_;
	for (int i=0; i<n; i++) r[i]++, c[i]++;
	for (int i=0; i<n; i++) {if (r[i]<c[i]) swap(r[i], c[i]);}
	for (int i=0; i<n; i++) im[i]={r[i],c[i]};

	sort(im, im+n, [](pii pi1, pii pi2){return pi1.fi==pi2.fi?pi1.se<pi2.se:pi1.fi>pi2.fi;});
	int mn=m+1;
	ar.push_back({0,0});
	for (int i=0; i<n; i++) {
		if (mn<=im[i].se) continue;
		ar.push_back({(ll)im[i].fi, (ll)im[i].se});
		mn=min(mn, im[i].se);
	}
	n=ar.size()-1;
	sort(ar.begin(), ar.end());
	ll s=-1, e=(m*m);
	while (s+1<e) {
		ll md=(s+e)/2;
		(f(md).fi>(ll)k?s:e)=md;
	}
	return f(e).se;
}

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