P1016求条

#include<bits/stdc++.h>
using namespace std;
double s,c,l,p0;
struct node{
	double d,p;
	bool operator<(node t)const{
		return d<t.d;
	}
}a[15];
int n;
int main(){
	cin>>s>>c>>l>>p0>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i].d>>a[i].p;
	}
	a[n+1].d=s;n++;
	sort(a+1,a+n+1);
	double sum=0,ans=0;int i;
	for(i=0;i<=n;){
		double minn=1e9;int id=-1;
		for(int j=i+1;j<=n&&a[i].d+c*l>=a[j].d;j++){
			if(a[j].p<p0){
				id=j;break;
			}
		}
		if(id!=-1){
			double k=(a[id].d-a[i].d)/l;
			ans+=(k-sum)*p0;
			sum=0;
			i=id;
			p0=a[id].p;continue;
		}
		if(s-a[i].d<=c*l){
			ans+=((s-a[i].d)/l-sum)*p0;
			break;
		}
		else{
			double minn=1e9;int id=-1;
			for(int j=i+1;j<=n&&a[i].d+c*l>=a[j].d;j++){
				if(a[j].p<=minn) minn=a[j].p,id=j;
			}
			ans+=c*p0;
			i=id;
			p0=a[id].p;
			sum=c;continue;
		}
		cout<<"No Solution";return 0;
	}
	cout<<fixed<<setprecision(2)<<ans;
	return 0;
}