如题

#include <bits/stdc++.h>

using namespace std;
int n,m,k,a,b[2005],c[2005],cnt,t,s;
int flag;
int ans;
int main()
{
    int i,j,t;
    cin>>n>>m>>k;
    int tt=k+k+1;
    for(i=1;i<=m;i++){
        cin>>a;
        s=a-k;
        if(s<=0)s=1;
        for(j=s;j<=a+k;j++){
            b[j]=1;
        }
    } b[n+1]=1;
    //for(i=1;i<=n;i++)cout<<b[i]<<" ";

    //cout<<endl;
    for(i=1;i<=n+1;i++){
        if(b[i]==0)flag=1,cnt++;
        if(b[i]==1&&flag==1)c[++t]=cnt,cnt=0,flag=0;
        if(b[i]==1&&flag==0);
    }
    for(i=1;i<=t;i++){
        if(c[i]>tt&&c[i]%tt>0){
            ans+=c[i]/tt+1;
            continue;
        }
        if(c[i]<=tt)ans++;
    }

    cout<<ans<<endl;
    return 0;
}