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.