Tower Defense 2

/*
    Task    :
    Author  : Phumipat C. [MAGCARI]
    Language: C++
    Created : 03 May 2023 [18:53]
*/
#include<bits/stdc++.h>
using namespace std;
struct A{
    int pos,v;
    bool operator < (const A&o) const{
        return pos < o.pos;
    }
};
A a[200010];
int main(){
    int n,m,k,w,sum = 0;
    cin >> n >> m >> k >> w;
    for(int i=1;i<=m;i++)
        cin >> a[i].pos;
    for(int i=1;i<=m;i++)
        cin >> a[i].v,sum+=a[i].v;
    sort(a+1,a+m+1);
    int lastUsed = 0;
    for(int i=1;i<=m;i++){
        int leftLimit = max(0,a[i].pos-w);
        leftLimit = max(leftLimit,lastUsed+1);
        if(leftLimit >= n+1)    break;
        int rightLimit = min({n,a[i].pos+w,leftLimit+a[i].v-1});
        int CanonNumber = min(rightLimit - leftLimit + 1,k);
        sum-=CanonNumber;
        k-=CanonNumber;
        lastUsed = rightLimit;
    }
    cout << sum << '\n';
    return 0;
}