C++ :

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<queue>
#define INF 10000000
#define N 1000010
using namespace std;
double ci[N],pi[N];
double dp[N];
int main()
{
    double l,c,m,s;
    int n;
    while(cin>>l>>c>>m>>pi[0]>>n)
    {
        for(int i=1;i<=n;i++)
        {
            scanf("%lf%lf",&ci[i],&pi[i]);
        }
        ci[0]=0,ci[n+1]=l,pi[n+1]=INF;
        s=c*m;
        for(int i=0;i<=n+1;i++)
            dp[i]=INF;
        dp[0]=0;
        int flag=0;
        for(int i=0;i<=n;i++)
        {
            for(int j=i+1;j<=n+1;j++)
            {
                if(s>=ci[j]-ci[i])
                {
                    dp[j]=min(dp[j],dp[i]+pi[i]*(ci[j]-ci[i])/m);
                }
                else
                {
                    if(s>=ci[j]-ci[j-1])
                        dp[j]=min(dp[j],dp[i]+(pi[i]*s+pi[j-1]*(ci[j]-ci[i]-s))/m);
                    else
                    {
                        flag=1;
                        break;
                    }
                }
            }
            if(flag==1)
                break;
        }
        if(dp[n+1]==INF)
            cout<<"No Solution"<<endl;
        else
            printf("%.2lf\n",dp[n+1]);
    }
    return 0;
}

Pascal :

var
 value,over,way,x:array[0..500]of real;
 l,c,dc,p0,ans:real;
 i,j,n:integer;
begin
 readln(l,c,dc,p0,n);
 for i:=1 to n do
   readln(way[i],value[i]);
 for i:=0 to n do
   begin over[i]:=0;x[i]:=0;end;
 inc(n);way[n]:=l;value[n]:=0;
 i:=0;
 l:=c*dc;
 value[0]:=p0;way[0]:=0;over[0]:=0;
 repeat
   j:=i+1;
   if way[j]-way[i]>l then begin writeln('No Solution');halt end;
   while way[j]-way[i]<=l do
     begin
       if value[j]<value[i] then break;
       inc(j);
     end;
   if way[j]-way[i]<=l then
     if over[i]*dc>=way[j]-way[i] then
       over[j]:=over[i]-(way[j]-way[i])/dc
     else x[i]:=(way[j]-way[i])/dc-over[i]
   else
   begin
     x[i]:=c-over[i];
     j:=i+1;
     over[j]:=c-(way[j]-way[i])/dc;
   end;
   i:=j;
 until i=n;
 ans:=0;
 for i:=0 to n-1 do
   ans:=ans+x[i]*value[i];
 writeln(ans:0:2);
end.

Java :

import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner sin = new Scanner(System.in);
        double totalDist = sin.nextDouble();
        double capacity = sin.nextDouble();
        double distPerGas = sin.nextDouble();
        double p0 = sin.nextDouble();
        int n = sin.nextInt();
        double[] dist = new double[n+2];
        double[] price = new double[n+1];
        dist[0] = 0.0;dist[n+1] = totalDist;
        price[0] = p0;
        for(int i=1;i<n+1;i++) {
            dist[i] = sin.nextDouble();
            price[i] = sin.nextDouble();
        }
        Deque<Node> queue = new LinkedList<>();
        double nowCapacity = 0.0;
        double cost = 0.0;
        for(int i=0;i<n+1;i++) {
            //装油
            if(queue.isEmpty()) {
                queue.add(new Node(price[0], capacity));
                nowCapacity = capacity;
            }else {
                //如果油箱里有贵的油，退掉
                while(!queue.isEmpty() && price[i] < queue.getLast().price) {
                    Node noNeedGas = queue.pollLast();
                    nowCapacity -= noNeedGas.cap;
                }
                //装油
                queue.add(new Node(price[i], capacity-nowCapacity));
                nowCapacity = capacity;
            }
            //烧油
            if(nowCapacity < (dist[i+1]-dist[i])/distPerGas) {
                System.out.println("No Solution");
                return;
            }else {
                //烧最便宜的
                double targetCapacity = (dist[i+1]-dist[i])/distPerGas;
                while(targetCapacity > 0.0) {
                    Node firstGas = queue.getFirst();
                    if(firstGas.cap >= targetCapacity) {
                        firstGas.cap -= targetCapacity;
                        cost += targetCapacity * firstGas.price;
                        nowCapacity -= targetCapacity;
                        targetCapacity = 0.0;
                    }else {
                        cost += firstGas.cap * firstGas.price;
                        targetCapacity -= firstGas.cap;
                        nowCapacity -= firstGas.cap;
                        queue.poll();
                    }
                }
            }
        }
        System.out.printf("%.2f%n", cost);
    }

}
class Node{
    double price;
    double cap;
    Node(double price, double cap){
        this.price = price;
        this.cap = cap;
    }
}