Submission #540399

#	Time	Username	Problem	Language	Result	Execution time	Memory
540399		krit3379	Watching (JOI13_watching)	C++14	100 / 100	207 ms	31696 KiB

watching

#include<bits/stdc++.h>
using namespace std;
#define N 2005

long long a[N],dp[N][N],l,r,mid,ans;

int main(){
    int n,i,j,p,q,prep,preq;
    scanf("%d %d %d",&n,&p,&q);
    for(i=1;i<=n;i++)scanf("%lld",&a[i]);
    sort(a+1,a+n+1);
    if(p+q>=n){printf("1");return 0;}
    l=1,r=1e9;
    while(l<=r){
        mid=(l+r)/2;
        for(i=n;i>0;i--){
            prep=lower_bound(a+1,a+n+1,a[i]+mid)-a;
            preq=lower_bound(a+1,a+n+1,a[i]+2*mid)-a;
            for(j=0;j<=p;j++){
                dp[i][j]=1e18;
                if(j>0)dp[i][j]=min(dp[i][j],dp[prep][j-1]);
                dp[i][j]=min(dp[i][j],dp[preq][j]+1);
            }
        }
        if(dp[1][p]<=q)ans=mid,r=mid-1;
        else l=mid+1;
    }
    printf("%lld",ans);
    return 0;
}

Compilation message (stderr)

watching.cpp: In function 'int main()':
watching.cpp:9:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |     scanf("%d %d %d",&n,&p,&q);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~
watching.cpp:10:27: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |     for(i=1;i<=n;i++)scanf("%lld",&a[i]);
      |                      ~~~~~^~~~~~~~~~~~~~

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