Submission #793253

#	Time	Username	Problem	Language	Result	Execution time	Memory
793253		alvingogo	Aliens (IOI16_aliens)	C++14	100 / 100	343 ms	39796 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define AquA cin.tie(0);ios_base::sync_with_stdio(0);
#define fs first
#define sc second
#define p_q priority_queue
#define sz(a) ((int)(a.size()))
using namespace std;
 
typedef long long ll;
typedef pair<ll,ll> pll;
vector<ll> v,nxt;
int lst=0,mn;
int n;
bool check1(pll a,pll b,int c){
    return a.fs*c+a.sc>b.fs*c+b.sc;
}
bool check2(pll a,pll b,pll c){
    return (b.sc-a.sc)*(b.fs-c.fs)<=(b.sc-c.sc)*(b.fs-a.fs);
}
ll get(ll p,bool x){
    vector<pair<pll,int> > dq;
    vector<pll> dp(n);
    int l=0;
    dq.push_back({{1-mn,1ll*(1-mn)*(1-mn)},0});
    //cout << p << ":\n";
    for(int i=0;i<n;i++){
        if(v[i]==n){
            continue;
        }
        while(sz(dq)-l>1 && check1(dq[l].fs,dq[l+1].fs,2*i)){
            l++;
        }
        dp[i].fs=2ll*i*dq[l].fs.fs+dq[l].fs.sc+1ll*i*i+p;
        dp[i].sc=dq[l].sc+1;
        ll xf=0;
        if(i>=nxt[i]){
            xf=-(i-nxt[i]+1)*(i-nxt[i]+1);
        }
        ll a=(1-nxt[i]),b=dp[i].fs+(1ll*(1-nxt[i])*(1-nxt[i]))+xf;
        while(sz(dq)-l>1 && check2(dq[sz(dq)-1].fs,dq[sz(dq)-2].fs,{a,b})){
            dq.pop_back();
        }
        dq.push_back({{a,b},dp[i].sc});
        /*
        cout << i << "\n";
        cout << "from: " << dq[l].fs.fs << " " << dq[l].fs.sc << "\n";
        for(int j=l;j<sz(dq);j++){
            cout << dq[j].fs.fs << " " << dq[j].fs.sc << "\n";
        }
        */
    }
    /*
    for(int i=0;i<n;i++){
        cout << dp[i].fs << " " << dp[i].sc << "\n";
    }
    cout << "\n";
    */
    if(x==0){
        return dp[lst].sc;
    }
    else{
        return dp[lst].fs;
    }
}
ll take_photos(int N, int M, int k, vector<int> R, vector<int> C) {
    n=M;
    int m=N;
    v.resize(n+1,n);
    nxt.resize(n);
    for(int i=0;i<m;i++){
        if(R[i]<C[i]){
            swap(R[i],C[i]);
        }
        v[R[i]]=min(v[R[i]],(ll)C[i]);
    }
    mn=n;
    for(int i=n-1;i>=0;i--){
        if(v[i]<mn){
            nxt[i]=mn;
            if(mn==n){
                lst=i;
            }
            mn=v[i];
        }
        else{
            v[i]=n;
        }
    }
    ll l=0,r=2e14;
    while(r>l){
        ll mid=(l+r)/2;
        if(get(mid,0)<=k){
            r=mid;
        }
        else{
            l=mid+1;
        }
    }
    return get(l,1)-l*k;
}

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