Submission #1023359

#	Time	Username	Problem	Language	Result	Execution time	Memory
1023359		vjudge1	Shortcut (IOI16_shortcut)	C++17	71 / 100	2048 ms	3672 KiB

shortcut

#include "shortcut.h"
#include <bits/stdc++.h>

#define ll long long
// #define int ll
#define pii pair<int,int>
#define F first
#define S second
#define sz(s) (int)s.size()
#define in insert
#define pb push_back
#define all(v) v.begin(),v.end()
#define mem(a,i) memset(a,i,sizeof(a))

using namespace std;

const int MAX=2e5+10;
const ll inf=1e18;

int n,c;
ll p[MAX];
pair<ll,ll> a[MAX],b[MAX];
vector<int> d;

bool check(ll L){
    ll sum[2][2]={{-inf,inf},{-inf,inf}};
    ll sum1[2][2]={{-inf,inf},{-inf,inf}};
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            if(i==j)continue;
            if(p[j]-p[i]+d[i]+d[j]<=L)continue;
            sum1[0][0]=max(sum1[0][0],p[i]+p[j]+d[i]+d[j]-L+c);
            sum1[1][1]=min(sum1[1][1],p[i]-d[i]+p[j]-d[j]+L-c);
            sum1[1][0]=max(sum1[1][0],p[j]+d[j]-p[i]+d[i]-L+c);
            sum1[0][1]=min(sum1[0][1],p[j]-d[j]-p[i]-d[i]+L-c);
        }
    }
    {
        int r=-1;
        pair<ll,ll> mx={-inf,-inf},mx1={-inf,-inf};
        for(int i=0;i<n;i++){
            while(r+1<n&&b[r+1].F<a[i].F-L){
                pair<ll,ll> bf={a[b[r+1].S].F,b[r+1].S};
                if(mx<bf){
                    mx1=mx;
                    mx=bf;
                }
                else if(mx1<bf){
                    mx1=bf;
                }
                r++;
            }
            if(i!=mx.S)sum[0][0]=max(sum[0][0],mx.F+a[i].F+c-L);
            else sum[0][0]=max(sum[0][0],mx1.F+a[i].F+c-L);
        }
    }
    {
        int r=-1;
        pair<ll,ll> mn={inf,inf},mn1={inf,inf};
        for(int i=0;i<n;i++){
            while(r+1<n&&b[r+1].F<a[i].F-L){
                pair<ll,ll> bf={-a[b[r+1].S].F,b[r+1].S};
                if(mn>bf){
                    mn1=mn;
                    mn=bf;
                }
                else if(mn1>bf){
                    mn1=bf;
                }
                r++;
            }
            if(i!=mn.S)sum[0][1]=min(sum[0][1],L-c+a[i].S+mn.F);
            else sum[0][1]=min(sum[0][1],L-c+a[i].S+mn1.F);
        }       
    }
    {
        int r=-1;
        pair<ll,ll> mn={inf,inf},mn1={inf,inf};
        for(int i=0;i<n;i++){
            while(r+1<n&&b[r+1].F<a[i].F-L){
                pair<ll,ll> bf={b[r+1]};
                if(bf<mn){
                    mn1=mn;
                    mn=bf;
                }
                else if(bf<mn1){
                    mn1=bf;
                }
                r++;
            }
            if(mn.S!=i)sum[1][1]=min(sum[1][1],mn.F+a[i].S+L-c);
            if(mn1.S!=i)sum[1][1]=min(sum[1][1],mn1.F+a[i].S+L-c);
        }
    }
    {
        int r=-1;
        pair<ll,ll> mx={-inf,-inf},mx1={-inf,-inf};
        for(int i=0;i<n;i++){
            while(r+1<n&&b[r+1].F<a[i].F-L){
                pair<ll,ll> bf={-b[r+1].F,b[r+1].S};
                if(bf>mx){
                    mx1=mx;
                    mx=bf;
                }
                else if(bf>mx1){
                    mx1=bf;
                }
                r++;
            }
            if(i!=mx.S)sum[1][0]=max(sum[1][0],a[i].F+mx.F+c-L);
            else sum[1][0]=max(sum[1][0],a[i].F+mx1.F+c-L);
        }
    }
    // cout<<sum[0][0]<<" "<<sum[1][1]<<" "<<sum[1][0]<<" "<<sum[0][1]<<"\n";
    // cout<<sum1[0][0]<<" "<<sum1[1][1]<<" "<<sum1[1][0]<<" "<<sum1[0][1]<<"\n";
    int r=-1;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            if(i==j)continue;
            if(sum[0][0]<=p[i]+p[j]&&p[i]+p[j]<=sum[1][1]&&sum[1][0]<=p[j]-p[i]&&p[j]-p[i]<=sum[0][1])return 1;
        }
        // while(r+1<i&&!(max(sum[1][1]+p[i],sum[0][0]-p[i])<=p[r]&&p[r]<=min(sum[1][0]-p[i],sum[0][1]+p[i])))r++;
        // if(r>=0&&max(sum[1][1]+p[i],sum[0][0]-p[i])<=p[r]&&p[r]<=min(sum[1][0]-p[i],sum[0][1]+p[i])){
        //     return 1;
        // }
    }
    return 0;
}

long long find_shortcut(int N, vector<int> G, vector<int> D, int C){
    n=N;
    c=C;
    d=D;
    for(int i=1;i<n;i++)p[i]=p[i-1]+G[i-1];
    for(int i=0;i<n;i++){
        // cout<<p[i]+d[i]<<"\n";
        a[i]={p[i]+d[i],p[i]-d[i]};
    }
    sort(a,a+n);
    for(int i=0;i<n;i++){
        b[i]={a[i].S,i};
    }
    sort(b,b+n);
    // cout<<check(51)<<"\n";
    // return 110;
    ll l=0,r=a[n-1].F-b[0].F-1,res=a[n-1].F-b[0].F;
    while(l<=r){
        ll m=(l+r)/2;
        if(check(m)){
            r=m-1;
            res=m;
        }
        else{
            l=m+1;
        }
    }
    return res;
}

Compilation message (stderr)

shortcut.cpp: In function 'bool check(long long int)':
shortcut.cpp:116:9: warning: unused variable 'r' [-Wunused-variable]
  116 |     int r=-1;
      |         ^

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 7 / 7
• Subtask 5: 33 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3