1521 一维战舰

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 
 4 const int MAX=2e5+10;
 5 int vis[MAX];
 6 
 7 int main(){
 8     int n,k,a,m,x;
 9     cin>>n>>k>>a>>m;
10     int flag=-1;
11     int left,right;
12     memset(vis,0,sizeof(vis));
13     int num=(n+1)/(a+1);
14     for(int i=0;i<m;i++){
15         cin>>x;
16         vis[x]=1;
17         for(left=x-1;left>0&&vis[left]==0;left--);
18         for(right=x+1;right<=n&&vis[right]==0;right++);
19         num-=(right-left)/(a+1)-(x-left)/(a+1)-(right-x)/(a+1);
20         if(num<k&&flag==-1){
21             flag=i+1;
22             break;
23         }
24     }
25     cout<<flag<<endl;
26     return 0;
27 }