Submission #995670

#	Time	Username	Problem	Language	Result	Execution time	Memory
995670		biank	Aliens (IOI16_aliens)	C++14	0 / 100	1 ms	420 KiB

aliens

#include<bits/stdc++.h>

using namespace std;

#define all(x) begin(x),end(x)
#define sz(x) int(x.size())
#define forn(i,n) for(int i=0;i<int(n);i++)

using vi=vector<int>;
using ll=long long;
using ld=long double;

using ii=pair<ll,ll>;
#define fst first
#define snd second

struct Line {
    ll m,b,k;
    ll operator()(ll x) {
        return m*x+b;
    }
    ld intersectX(Line &o) {
        return ld(b-o.b)/(o.m-m);
    }
};
 
struct LineContainer:deque<Line>{
    void add(ll m, ll b, ll k){
        Line l=Line{m,b,k};
        while(size()>=2&&l.intersectX(begin()[0])<=l.intersectX(begin()[1])) pop_front();
        push_front(l);
    }
    pair<ll,int> query(ll x){
        while(size()>=2&&end()[-1](x)>=end()[-2](x)) pop_back();
        return {end()[-1](x),end()[-1].k};
    }
};

vector<ii> p;

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

ii check(ll lmd){
    LineContainer dp;
    ll res=0,cnt=0;
    forn(i,sz(p)){
        ll m=-2LL*(p[i].snd-1LL);
        ll b=res+sq(p[i].snd-1LL);
        if(i) b-=sq(max(p[i-1].fst-p[i].snd+1LL,0LL));
        dp.add(m,b,cnt);
        tie(res,cnt)=dp.query(p[i].fst);
        res+=sq(p[i].fst)+lmd,cnt++;
    }
    return {res,cnt};
}

ll take_photos(int n, int /*m*/, int k, vi r, vi c){
    vector<ii> v(n);
    forn(i,n){
        if(r[i]<c[i]) v[i]={r[i],c[i]};
        else v[i]={c[i],r[i]};
    }
    sort(all(v),[](const ii &a, ii &b){
        if(a.fst==b.fst) return a.snd>b.snd;
        return a.fst<b.fst;
    });
    p.clear();
    forn(i,n){
        if(p.empty()||p.back().snd<v[i].snd) p.push_back(v[i]);
    }
    k=min(k,sz(p));
    ll lo=0, hi=1e13;
    while(hi-lo>1){
        ll mid=(hi-lo)/2+lo;
        if(check(mid).snd<=k) hi=mid;
        else lo=mid;
    }
    return check(hi).fst-k*hi;
}

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