Submission #1209758

#	Time	Username	Problem	Language	Result	Execution time	Memory
1209758		Warinchai	Watching (JOI13_watching)	C++20	100 / 100	400 ms	31900 KiB

watching

#include<bits/stdc++.h>
#define int long long
using namespace std;
int n,p,q;
int dp[2005][2005];
int curs[2005];
int curb[2005];
int inf=1e9;
vector<int>v;

bool check(int x){
    //cerr<<x<<"\n";
    for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)dp[i][j]=inf;
    for(int i=0;i<=p;i++)curs[i]=curb[i]=0;
    for(int i=1;i<=n;i++){
        for(int j=0;j<=p;j++){
            while(curb[j]<n&&v[curb[j]]<=v[i-1]-2*x)curb[j]++;
            int id=curb[j];
            dp[i][j]=dp[id][j]+1;
            while(curs[j]<n&&v[curs[j]]<=v[i-1]-x)curs[j]++;
            id=curs[j];
            if(j!=0)dp[i][j]=min(dp[i][j],dp[id][j-1]);
        }
    }
    if(dp[n][p]<=q)return true;
    return false;
}

int32_t main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>p>>q;
    for(int i=1;i<=n;i++){
        int x;cin>>x;
        v.push_back(x);
    }
    sort(v.begin(),v.end());
    if(p+q>=n){
        cout<<1;
        return 0;
    }
    long long st=1,en=1e9;
    int ans=0;
    while(st<=en){
        long long m=(st+en)/2;
        if(check(m)){
            ans=m;
            en=m-1;
        }else{
            st=m+1;
        }
    }
    cout<<ans;
}

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50