Submission #930756

#	Time	Username	Problem	Language	Result	Execution time	Memory
930756		guagua0407	Aliens (IOI16_aliens)	C++17	4 / 100	2 ms	1884 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=1e5+5;
const ll inf=1e18;
vector<pair<ll,ll>> dp(mxn);
vector<int> x,y;

ll c(int l,int r){
    if(l>r) return 0;
    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;
}

int search(int i,int j,int l,int r){
    if(l==r) return l;
    else{
        int mid=(l+r+1)/2;
        if(make_pair(dp[i].f+c(i+1,mid),dp[i].s)<make_pair(dp[j].f+c(j+1,mid),dp[j].s)){
            return search(i,j,mid,r);
        }
        else{
            return search(i,j,l,mid-1);
        }
    }
}

ll check(int n,ll cost){
    deque<pair<int,int>> dq;
    dq.push_back({0,n+1});
    dp[0]={0,0};
    for(int i=1;i<=n;i++){
        while(dq.front().s<i) dq.pop_front();
        int j=dq.front().f;
        dp[i].f=dp[j].f+c(j+1,i)+cost;
        dp[i].s=dp[j].s+1;
        while(dq.size()>1 and make_pair(search(j,i,i,n),-dp[j].s)<=make_pair(dq[dq.size()-2].s,-dp[dq[dq.size()-2].f].s)){
            dq.pop_back();
            j=dq.back().f;
        }
        dq.back().s=search(j,i,i,n);
        dq.push_back({i,n+1});
    }
    return dp[n].s;
}

ll solve(int n,int m,int k){
    k=min(k,n);
    ll l=0,r=(ll)1e12+1;
    while(l<r){
        ll mid=(l+r)/2;
        if(check(n,mid)<=k){
            r=mid;
        }
        else{
            l=mid+1;
        }
    }
    check(n,l);
    return dp[n].f-k*l;
}

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