Submission #294529

#	Time	Username	Problem	Language	Result	Execution time	Memory
294529		daniel920712	Aliens (IOI16_aliens)	C++14	100 / 100	249 ms	9924 KiB

aliens

#include "aliens.h"
#include <algorithm>
#include <deque>
using namespace std;
struct A
{
    long long a;
    long long b;
}Node[100005],ttt[100005];
bool ok[100005]={0};
long long DP[100005];
long long con[100005]={0};
long long tt[100005];
deque <  pair < pair < long long , long long > , long long > > L;
bool cmp(A a,A b)
{
    return a.b<b.b||a.b==b.b&&a.a>b.a;
}

long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c)
{
    long long i,j,N=0,ll,rr,ans=1e18,mid,l1,l2,r1,r2;
    pair < pair < long long , long long >, long long > x,y,z;
    for(i=0;i<n;i++)
    {
        ttt[i].a=(long long) max(r[i],c[i]);
        ttt[i].b=(long long) min(r[i],c[i]);
    }
    sort(ttt,ttt+n,cmp);
    ll=ttt[0].b;
    rr=ttt[0].a;
    for(i=1;i<n;i++)
    {
        if(ll<=ttt[i].b&&ttt[i].a<=rr) ok[i]=1;
        else
        {
            ll=ttt[i].b;
            rr=ttt[i].a;
        }
    }
    for(i=0;i<n;i++) if(!ok[i]) Node[N++]=ttt[i];
    sort(Node,Node+N,cmp);
    Node[N].b=1e9;
    tt[N]=1e9;
    for(i=N-1;i>=0;i--) tt[i]=min(tt[i+1],Node[i].b);
    ll=0;
    rr=(long long) m*(long long) m;
    //printf("%lld %lld\n",ll,rr);
    while((rr-ll)>1)
    {
        mid=(rr+ll)/2;
        L.clear();
        for(j=0;j<N;j++)
        {
            DP[j]=1e18;
            if(j==0) z=make_pair(make_pair(-2*Node[j].b,(Node[j].b)*Node[j].b),(long long) 0);
            else z=make_pair(make_pair(-2*Node[j].b,DP[j-1]+(Node[j].b)*Node[j].b),con[j-1]);
            if(!L.empty())
            {
                x=L.back();
                L.pop_back();
                while(!L.empty()&&((double) (z.first.first-x.first.first)/(double) (x.first.second-z.first.second))>=((double) (L.back().first.first-x.first.first)/(double) (x.first.second-L.back().first.second)))
                {
                    x=L.back();
                    L.pop_back();
                }
                L.push_back(x);
            }
            if(L.empty()||L.back().first.first!=z.first.first) L.push_back(z);
            x=L.front();
            L.pop_front();
            while(!L.empty()&&x.first.first*(Node[j].a+1)+x.first.second>=L.front().first.first*(Node[j].a+1)+L.front().first.second)
            {
                x=L.front();
                L.pop_front();
            }
            L.push_front(x);
            DP[j]=x.first.first*(Node[j].a+1)+x.first.second;
            DP[j]+=(Node[j].a+1)*(Node[j].a+1);
            DP[j]-=max((long long) 0,Node[j].a-Node[j+1].b+1)*max((long long) 0,Node[j].a-Node[j+1].b+1);

            DP[j]+=mid;
            con[j]=x.second+1;

        }
        if(con[N-1]<k) rr=mid;
        else ll=mid;

    }

    L.clear();
    for(j=0;j<N;j++)
    {
        DP[j]=1e18;
        if(j==0) z=make_pair(make_pair(-2*Node[j].b,(Node[j].b)*Node[j].b),(long long) 0);
        else z=make_pair(make_pair(-2*Node[j].b,DP[j-1]+(Node[j].b)*Node[j].b),con[j-1]);
        if(!L.empty())
        {
            x=L.back();
            L.pop_back();
            while(!L.empty()&&((double) (z.first.first-x.first.first)/(double) (x.first.second-z.first.second))>=((double) (L.back().first.first-x.first.first)/(double) (x.first.second-L.back().first.second)))
            {
                x=L.back();
                L.pop_back();
            }
            L.push_back(x);
        }
        if(L.empty()||L.back().first.first!=z.first.first) L.push_back(z);
        x=L.front();
        L.pop_front();
        while(!L.empty()&&x.first.first*(Node[j].a+1)+x.first.second>=L.front().first.first*(Node[j].a+1)+L.front().first.second)
        {
            x=L.front();
            L.pop_front();
        }
        L.push_front(x);
        DP[j]=x.first.first*(Node[j].a+1)+x.first.second;
        DP[j]+=(Node[j].a+1)*(Node[j].a+1);
        DP[j]-=max((long long) 0,Node[j].a-Node[j+1].b+1)*max((long long) 0,Node[j].a-Node[j+1].b+1);

        DP[j]+=ll;
        con[j]=x.second+1;

    }

    if(con[N-1]==k) return DP[N-1]-ll*con[N-1];
    l1=DP[N-1]-ll*con[N-1];
    l2=con[N-1];

    L.clear();
    for(j=0;j<N;j++)
    {
        DP[j]=1e18;
        if(j==0) z=make_pair(make_pair(-2*Node[j].b,(Node[j].b)*Node[j].b),(long long) 0);
        else z=make_pair(make_pair(-2*Node[j].b,DP[j-1]+(Node[j].b)*Node[j].b),con[j-1]);
        if(!L.empty())
        {
            x=L.back();
            L.pop_back();
            while(!L.empty()&&((double) (z.first.first-x.first.first)/(double) (x.first.second-z.first.second))>=((double) (L.back().first.first-x.first.first)/(double) (x.first.second-L.back().first.second)))
            {
                x=L.back();
                L.pop_back();
            }
            L.push_back(x);
        }
        if(L.empty()||L.back().first.first!=z.first.first) L.push_back(z);
        x=L.front();
        L.pop_front();
        while(!L.empty()&&x.first.first*(Node[j].a+1)+x.first.second>=L.front().first.first*(Node[j].a+1)+L.front().first.second)
        {
            x=L.front();
            L.pop_front();
        }
        L.push_front(x);
        DP[j]=x.first.first*(Node[j].a+1)+x.first.second;
        DP[j]+=(Node[j].a+1)*(Node[j].a+1);
        DP[j]-=max((long long) 0,Node[j].a-Node[j+1].b+1)*max((long long) 0,Node[j].a-Node[j+1].b+1);

        DP[j]+=(ll+1);
        con[j]=x.second+1;

    }
    if(con[N-1]==k) return DP[N-1]-(ll+1)*con[N-1];
    r1=DP[N-1]-(ll+1)*con[N-1];
    r2=con[N-1];
    if(r2==l2) return r1;
    return l1+(r1-l1)*(k-l2)/(r2-l2);

}

Compilation message (stderr)

aliens.cpp: In function 'bool cmp(A, A)':
aliens.cpp:17:29: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   17 |     return a.b<b.b||a.b==b.b&&a.a>b.a;
      |                     ~~~~~~~~^~~~~~~~~
aliens.cpp: In function 'long long int take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:22:29: warning: unused variable 'ans' [-Wunused-variable]
   22 |     long long i,j,N=0,ll,rr,ans=1e18,mid,l1,l2,r1,r2;
      |                             ^~~

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