spoj PIGBANK TLE even though i am using DP

general
1 
#include <iostream>
using namespace std;
//typedef long long int lint;
#define INF 1000000000
int dp[10001];
int coins(int wt,int a[],int v[],int n)
{
   if(wt<0)
   return INF;
      
   if(wt==0)
   return 0;

   if(dp[wt]!=INF)
   return dp[wt];

   for(int i=0;i<n;i++)
   {   int k=coins(wt-a[i],a,v,n);
      if(v[i]+k<dp[wt])
      dp[wt]=v[i]+k;
   }
   return dp[wt];   

}
int main() {
   ios_base::sync_with_stdio(false);
   
   int t;
   cin>>t;
   while(t--)
   {   int e,f;
      cin>>e>>f;
      int wt=f-e;
      for(int i=0;i<wt+1;i++)
      dp[i]=INF;

      int n;
      cin>>n;
      int a[n],v[n];
      for(int i=0;i<n;i++)
      cin>>v[i]>>a[i];

      int m=coins(wt,a,v,n);
      
         if(m==INF)
         cout<<"This is impossible.\n";
         else
               cout<<"The minimum amount of money in the piggy-bank is "<<m<<"."<<endl;


   }
   return 0;
}
2

Here is My AC solution to this problem. I have coded it very simple so that you can understand every part of it.

Have a look it might help you in figuring out your mistake .

3

Please either paste the code in the correct format or just provide the link on ideone or on codechef compiler .

4

thanks for the reply.I see you have used bottom-up approach .I converted my top-down approach to bottom up it got accepted.Does anyone know why?