#include<bits/stdc++.h>
#define Gc() getchar()
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define eb emplace_back
#define all(x) x.begin(),x.end()
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;
const int N=2e5+5,M=(1<<28)+5,K=1000+5,mod=1e9+7,Mod=mod-1;const db eps=1e-9;const int INF=1e9+7;mt19937 rnd(28382);
#define Tp template<typename T>
#define Ts template<typename T,typename... Ar>
namespace Debug{
	Tp void _debug(char* f,T t){cerr<<f<<'='<<t<<endl;}
	Ts void _debug(char* f,T x,Ar... y){while(*f!=',') cerr<<*f++;cerr<<'='<<x<<",";_debug(f+1,y...);}
	#ifdef LOCAL
	#define gdb(...) _debug((char*)#__VA_ARGS__,__VA_ARGS__)
	#else 
	#define gdb(...) void()
	#endif
}using namespace Debug;
int n,m,q,T,X[N],Y[N];
int A[N];
ll ans[N];
void work(){
	
}
void Solve(){
	scanf("%d%d%d%d",&n,&m,&q,&T);
	for(int i=1;i<=n;i++) scanf("%d",&A[i]);
	for(int i=1;i<=q;i++) scanf("%d%d",&X[i],&Y[i]);
	for(int i=1;i<=q;i++){
		if(Y[i]>=A[X[i]]){
			int p=UB(A+1,A+n+1,Y[i])-A-1;
			for(int k=0;k<m;k++){
				ll mx=-1e18;
				auto merge=[&](int x){
					if(mx<x) mx=x+T;
					else ans[i]+=mx-x,mx+=T;
				};
				gdb(p);
				for(int j=1;j<X[i];j++) if(j%m==k) merge(A[j]);
				for(int j=X[i]+1;j<=p;j++) if((j-1)%m==k) merge(A[j]);
				if(p%m==k) merge(Y[i]);
				for(int j=p+1;j<=n;j++) if(j%m==k) merge(A[j]);
			}
		}else{
			int p=LB(A+1,A+n+1,Y[i])-A;
			for(int k=0;k<m;k++){
				ll mx=-1e18;
				auto merge=[&](int x){
					if(mx<x) mx=x+T;
					else ans[i]+=mx-x,mx+=T;
				};
				gdb(p);
				for(int j=1;j<p;j++) if(j%m==k) merge(A[j]);
				if(p%m==k) merge(Y[i]);
				for(int j=p;j<X[i];j++) if((j+1)%m==k) merge(A[j]);
				for(int j=X[i]+1;j<=n;j++) if(j%m==k) merge(A[j]);
			}
		}
	}
	for(int i=1;i<=q;i++) printf("%lld\n",ans[i]);
}
int main(){
	int t=1;
	// scanf("%d",&t);
	while(t--) Solve();
	cerr<<clock()*1.0/CLOCKS_PER_SEC<<'\n';
}