C :

#include <stdio.h>
#define N 1024

int main()
{
    int i,j,k,n;
    double d1,c,d2,p[N][2]={0},f,min;
    scanf("%lf%lf%lf%lf%d",&d1,&c,&d2,&p[0][1],&n);
    n++;
    for (i=1;i<n;i++)
        scanf("%lf%lf",&p[i][0],&p[i][1]);
    p[n++][0]=d1;
    f=c*d2;
    for(i=0;i<n;i++)
    {
        if (p[i+1][0]-p[i][0]>f)
        {
            printf("No Solution");
            return 0;
        }
    }
    k =0;
    min=0;
    for (i=0;i<n-1;i++)
    {
        double d=p[i+1][0]-p[i][0];
        while(d)
        {
            while(p[i+1][0]-p[k][0]-d>= f)
                k++;
            for(j=k;j<= i;j++)
                if (p[j][1]<p[k][1])
                    k=j;
            double max=f-(p[i+1][0]-p[k][0]-d);
            if(max>d)max=d;
            d-=max;
            min+=max/d2*p[k][1];
        }
    }
    printf("%.2lf\n",min);
    return 0;
}

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 dis,c,m,l,ans,t:real;
    n,i,j:longint;
    over,x,p,d:array[0..1000] of real;
begin
  readln(dis,c,m,p[0],n);
  l:=c*m;
  for i:=1 to n do
    readln(d[i],p[i]);
  d[n+1]:=dis;
  for i:=1 to n+1 do
    if d[i]-d[i-1]>l then begin writeln('No Solution'); exit end;
  i:=0;
  repeat
    for j:=i+1 to n+2 do
      if (d[j]-d[i]<=l) and (p[j]<p[i]) then break;
    t:=(d[j]-d[i])/m;
    if j<>n+2 then
    begin
      if over[i]>=t then
        over[j]:=over[i]-t
      else
        x[i]:=t-over[i]
    end
    else
    begin
      x[i]:=c-over[i];
      j:=i+1;
      over[j]:=c-(d[j]-d[i])/m;
    end;
    i:=j;
  until i=n+1;
  for i:=0 to n do
    ans:=ans+p[i]*x[i];
  writeln(ans:0:2);
end.