Submission #51469

#	Time	Username	Problem	Language	Result	Execution time	Memory
51469		mergesort	Watching (JOI13_watching)	C++14	50 / 100	108 ms	4092 KiB

watching

#include<bits/stdc++.h>
using namespace std;
int a[2005],n,p,q;
int len1[2005],len2[2005],dp[2005][2005];
bool check(int w)
{
    for(int i=1;i<=n;++i){
        len1[i]=len2[i]=i;
        for(int j=i+1;j<=n;++j){
            if(a[i]+w-1>=a[j])len1[i]=j;
            if(a[i]+2*w-1>=a[j])len2[i]=j;
        }
    }
    len1[n+1]=len2[n+1]=n;
    dp[0][1]=len2[1];dp[1][0]=len1[1];
    for(int i=1;i<=p;++i){
        for(int j=1;j<=q;++j){
            int pos1=dp[i-1][j],pos2=dp[i][j-1];
            if(pos1>=n || pos2>=n)dp[i][j]=n;pos1++;pos2++;
            dp[i][j]=max(len1[pos1],len2[pos2]);
        }
    }
    if(dp[p][q]>=n)return true;
    else return false;
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin>>n>>p>>q;
    for(int i=1 ;i<=n;++i)cin>>a[i];
    sort(a+1,a+1+n);
    if(p+q>=n){
        cout<<"1";
        return 0;
    }
    int l=0,r=1e9;
    while(l+1<r){
        int mid=(l+r)/2;
        if(check(mid))r=mid;
        else l=mid;
    }
    //cout<<check(4)<<"\n****"<<endl;
    int ans=1e9;
    if(check(r))ans=min(ans,r);
    if(check(l))ans=min(ans,l);
    cout<<ans;
}

Compilation message (stderr)

watching.cpp: In function 'bool check(int)':
watching.cpp:19:13: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
             if(pos1>=n || pos2>=n)dp[i][j]=n;pos1++;pos2++;
             ^~
watching.cpp:19:46: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
             if(pos1>=n || pos2>=n)dp[i][j]=n;pos1++;pos2++;
                                              ^~~~

• Subtask 1: 50 / 50
• Subtask 2: 0 / 50