Submission #930472

#	Time	Username	Problem	Language	Result	Execution time	Memory
930472		guagua0407	Aliens (IOI16_aliens)	C++17	60 / 100	278 ms	12232 KiB

aliens

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#include "aliens.h"
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}
const int mxn=5e4+5;
const ll inf=1e18;
vector<ll> dp(mxn,inf),tmp(mxn,inf);
vector<int> x,y;

ll cost(int l,int r){
    ll a=(y[r]-x[l]+1);
    ll b=(l==1?0:max(0,y[l-1]-x[l]+1));
    return a*a-b*b;
}

void go(int l,int r,int tl,int tr,int id){
    if(l>r){
        return;
    }
    int mid=(l+r)/2;
    int pos=tl;
    ll best=inf;
    for(int i=tl;i<=min(mid-1,tr);i++){
        ll cur=tmp[i]+cost(i+1,mid);
        if(cur<best){
            pos=i;
            best=cur;
        }
    }
    dp[mid]=best;
    go(l,mid-1,tl,pos,id);
    go(mid+1,r,pos,tr,id);
}

ll solve(int n,int m,int k){
    ll ans=inf;
    tmp[0]=0;
    for(int t=1;t<=k;t++){
        go(1,n,0,n,t);
        ans=min(ans,dp[n]);
        for(int i=0;i<=n;i++){
            tmp[i]=dp[i];
            dp[i]=inf;
        }
    }
    return ans;
}

ll take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c){
    vector<pair<int,int>> vec(n);
    for(int i=0;i<n;i++){
        if(r[i]>c[i]) swap(r[i],c[i]);
        vec[i]={c[i],r[i]};
    }
    sort(all(vec));
    vector<pair<int,int>> st;
    for(int i=0;i<n;i++){
        while(!st.empty() and st.back().s>=vec[i].s){
            st.pop_back();
        }
        st.push_back(vec[i]);
    }
    x.push_back(-1);
    y.push_back(-1);
    for(auto v:st){
        x.push_back(v.s);
        y.push_back(v.f);
    }
    return solve(st.size(),m,k);
}
//maybe its multiset not set
//yeeorz
//laborz

Compilation message (stderr)

aliens.cpp: In function 'void setIO(std::string)':
aliens.cpp:16:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
aliens.cpp:17:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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