Submission #35031

#	Time	Username	Problem	Language	Result	Execution time	Memory
35031		dqhungdl	Watching (JOI13_watching)	C++14	100 / 100	519 ms	17724 KiB

watching

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

int n,P,Q,a[2005],f[2005][2005];

bool Check(int w)
{
    for(int i=0;i<=n;i++)
        for(int j=0;j<=P;j++)
            f[i][j]=1e9;
    f[0][0]=0;
    for(int i=1;i<=n;i++)
    {
        int id1,id2;
        for(int j=1;j<=i;j++)
            if(a[i]-a[j]+1<=w)
            {
                id1=j;
                break;
            }
        for(int j=1;j<=i;j++)
            if(a[i]-a[j]+1<=2*w)
            {
                id2=j;
                break;
            }
        for(int j=1;j<=P;j++)
            f[i][j]=min(f[i][j],f[id1-1][j-1]);
        for(int j=0;j<=P;j++)
            f[i][j]=min(f[i][j],f[id2-1][j]+1);
    }
    for(int j=0;j<=P;j++)
        if(f[n][j]<=Q)
            return true;
    return false;
}

int main()
{
    cin>>n>>P>>Q;
    P=min(P,n);
    Q=min(Q,n);
    for(int i=1;i<=n;i++)
        cin>>a[i];
    sort(a+1,a+n+1);
    int res,l=1,r=1e9;
    while(l<=r)
    {
        int mid=(l+r)/2;
        if(Check(mid)==true)
        {
            res=mid;
            r=mid-1;
        }
        else
            l=mid+1;
    }
    cout<<res;
}

Compilation message (stderr)

watching.cpp: In function 'bool Check(int)':
watching.cpp:14:17: warning: 'id2' may be used uninitialized in this function [-Wmaybe-uninitialized]
         int id1,id2;
                 ^
watching.cpp:14:13: warning: 'id1' may be used uninitialized in this function [-Wmaybe-uninitialized]
         int id1,id2;
             ^
watching.cpp: In function 'int main()':
watching.cpp:58:14: warning: 'res' may be used uninitialized in this function [-Wmaybe-uninitialized]
     cout<<res;
              ^

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