数据为啥会RE

#include<bits/stdc++.h>
using namespace std;
int main(){
	int t;
	cin>>t;
	while(t--){
		long long a,b,k,l;long long aa = 0,bb = 0,sum = 0;
		cin>>a>>b>>k>>l;
		if(l <= a&&l <= b){
			aa = a/l,bb = b/l;
			if(aa+bb <= k){
				sum = a%l+b%l;
				cout<<sum<<endl;
			} 
			else{
				sum = a%l+b%l+(aa + bb - k)*l;
				cout<<sum<<endl;
			}
		}
		else if(l <= a&&l > b){
			aa = a/l;
			if(aa <= k){
				sum = a%l+b;
				cout<<sum<<endl;
			}
			else{
				sum = a%l+b+(aa - k)*l;
				cout<<sum<<endl;
			}
		}
		else if(l > a&&l <= b){
			bb = b/l;
			if(bb <= k){
				sum = a+b%l;
				cout<<sum<<endl;
			}
			else{
				sum = a+b%l+(bb - k)*l;
				cout<<sum<<endl;
			}
		}
		else{
			sum = a+b;
			cout<<sum<<endl;
		}
	}
}

求救