Submission #1192758

#	Time	Username	Problem	Language	Result	Execution time	Memory
1192758		simona1230	Aliens (IOI16_aliens)	C++20	60 / 100	249 ms	3396 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>
using namespace std;

int num;
pair<int,int> p[200001];
bool cmp(pair<int,int> p1,pair<int,int> p2)
{
    if(p1.second==p2.second)return p1.first<p2.first;
    return p1.second<p2.second;
}


long long sq(long long x)
{
    return x*x;
}
long long dp[50001][2];
void compute(int j,int l,int r,int optl,int optr)
{
    if(l>r)return;
    int m=(l+r)/2;
    //cout<<j<<" "<<l<<" "<<r<<" "<<optl<<" "<<optr<<endl;
    int opt=optl;
    for(int i=optl;i<=min(optr,m);i++)
    {
        if(i==0)
        {
            dp[m][j]=sq(p[m].second-p[0].first+1);
            continue;
        }

        long long h=dp[i-1][1^j]+sq(p[m].second-p[i].first+1)-sq(max(0,p[i-1].second-p[i].first+1));
        dp[m][j]=min(dp[m][j],h);
        if(dp[m][j]==h)opt=i;
    }

    if(l==r)return;
    compute(j,l,m,optl,opt);
    compute(j,m+1,r,opt,optr);
}

long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c)
{
    for(int i=0; i<n; i++)
        p[i]= {min(r[i],c[i]),max(r[i],c[i])};
    sort(p,p+n,cmp);
    for(int i=0; i<n; i++)
    {
        if(i!=0&&p[i].second==p[i-1].second)continue;
        while(num!=0&&p[num-1].first>=p[i].first)num--;
        p[num++]=p[i];
    }

    /*cout<<num<<endl;
    for(int i=0;i<num;i++)
        cout<<p[i].first<<" "<<p[i].second<<endl;*/
    for(int i=0; i<num; i++)
    {
        for(int j=0; j<=k; j++)
        {
            dp[i][j]=1e18;
        }
    }

    long long ans=1e18;

    for(int i=0;i<num;i++)
        dp[i][1]=sq(p[i].second-p[0].first+1);
    ans=dp[num-1][1];

    int now=1,old=0;
    for(int j=2;j<=k;j++)
    {
        swap(now,old);
        for(int i=0;i<num;i++)
            dp[i][now]=1e18;

        compute(now,0,num-1,0,num-1);
        ans=min(ans,dp[num-1][now]);
    }

    return ans;
}

Compilation message (stderr)

aliens.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~
aliens_c.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~

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