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 }