Piggy bank.cpp

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;

#include<bits/stdc++.h>
#include<cmath>
#include<cstdlib> //for qsort
#include<cstdio>

#define rep(x,a,b) for(x=a;x<b;x++)
#define reptill(x,a,b) for(x=a;x<=b;x++)

#define scani(x) scanf("%d",&x)
#define scan2i(x,y) scanf("%d %d",&x,&y)
#define scan3i(x,y,z) scanf("%d %d %d",&x,&y,&z)

#define scanfl(x) scanf("%f",&x)
#define scanc(x) scanf("%c",&x)
#define scand(x) scanf("%lf",&x)

#define scanll(x) scanf("%lli",&x)
#define scan2ll(x,y) scanf("%lli %lli",&x,&y)
#define scan3ll(x,y,z) scanf("%lli %lli %lli",&x,&y,&z);

#define scanl(x) scanf("%ld",&x)
#define scans(x) scanf("%s",x)
#define printi(x) printf("%d\n",x)
#define printl(x) printf("%ld\n",x)
#define printll(x) printf("%lli\n",x)
#define printd(x) printf("%lf\n",x)
#define printfl(x) printf("%f\n",x)
#define printc(x) printf("%c\n",x)
#define prints(x) printf("%s\n",x);
#define sloop(x) loop(i,0,strlen(x)-1)
#define newl cout<<"\n"
#define FILL(A,value) memset(A,value,sizeof(A))


#define whole(x) x.begin(),x.end()
#define pb push_back
#define in insert
#define mp make_pair
#define get(tp_name,x) (get<x>(tp_name))   ///to access tuple(i)
#define umap unordered_map



using namespace std;


#define F first
#define S second



///Optional

///vector< vector<int> > costs(N, vector<int>(M, 0));   //NxM 2d preinitialized(0) vector

 ///comparator class for ordering on the basis of 'Second'
/*
class CompareDist
{
	public:				///pairType doesn't name a type ,its just to show type of pair object passed in operatorfunction

    bool operator()( pairType p1, pairType p2) {
        return p1.S>p2.S;
    }
};
*/

typedef pair<int,int> II;
typedef pair<ll,ll> LL;
typedef vector<II> VII;
typedef vector<LL> VLL;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector< VI > VVI;
typedef vector< VL > VVL;
typedef vector<string> VS;

inline bool inc_range(int x,int y,int z) { return ((x>=y)&&(x<=z)); }
inline bool ex_range(int x,int y,int z) { return ((x>y)&&(x<z)); }
inline bool is_either(int x,int y,int z) { return ((x==y)||(x==z)); }

//maths
#define PI acos(-1)

#define INTmax numeric_limits<int>::max()
#define LLmax numeric_limits<ll>::max()
#define ULLmax numeric_limits<ull>::max()

#define INTmin numeric_limits<int>::min()


typedef priority_queue<II,vector<II>, greater<II> > P_Queue;             ///priority queue contianing II (having vector<II> as underlying container) with greater as functor
																		///		heapify on the basis of comparisons of  II.first  values

template<typename type>
void get_arr(type a[],type n) {for(type i=0;i<n;i++) cin>>a[i];}

template<typename type>
void show_arr(type a[],type n=1) {for(type i=0;i<n;i++) cout<<a[i]<<" ";}

template<typename type>
inline type max3(type a,type b,type c){	 return max(max(a,b),c);}

template<typename type>
inline type min3(type a,type b,type c){	 return min(a,min(b,c));}

template<typename type>
inline type min4(type a,type b,type c,type d){	 return min(a,min3(b,c,d));}


template<typename type>
type modpowIter(type a, type b, type c) { type ans=1;  while(b != 0){ if(b%2 == 1) ans=(ans*a)%c;  a=(a*a)%c; b /= 2; } return ans; }

template<typename type>
type phi(type n){ type result = n;  for (type p=2; p*p<=n; ++p) { if (n % p == 0){ while (n % p == 0)   n /= p; result -= result / p; } }
if (n > 1) result -= result / n; return result;
}

template<class type>
type ncr(type n,type r)
{  	assert(n>=r);
	type ans=1,i;
	if(n==r) return 1; if(r==1) return n; if(r>(n-r)) r=n-r;
	reptill(i,0,r-1) ans=ans*(n-i)/(i+1);
	return ans;
}
template<typename type>  unsigned long long fact(type x){ ull ans=1; for(type i=1;i<=x;i++){ ans*=i;        /*ans%=MOD;   /Optional*/ } return ans; }

inline void FAST_IO(){ios_base::sync_with_stdio(false);}



#define SIZE (int(1e5)+1)
#define MOD
#define debug
#define MAX1
#define MAX2

//#define Online_judge




///Let dp(w) denotes the min amount which can be made with a given weight of w

VI memo;

///memo[x]=-1 denotes state x hasn't been soved yet

int dp(int x,VII & info)
{
	//cout<<"called for "<<x<<"\n";
	if(x==0)
	 return 0;

	if(x<0)
	 return -2;

	assert(x>=0 and x<SIZE);

	if(memo[x]!=-1)
	 return memo[x];

	 int state_ans=INTmax;

	 for(int i=0;i<info.size();i++)
	 {
			int resp = dp(x-info[i].S,info);

			//cout<<"Hello\n";
			if(resp!=-2)
			 state_ans= min(state_ans, info[i].F + resp);
		}


	if(state_ans!=INTmax)	  memo[x]=state_ans;		/// Memo x =-2 denotes that this state can't take us to the exact weight
	else memo[x]=-2;

	return memo[x];
}

int main()
{

	FAST_IO();

    //	ifstream cin("/home/aditya/Documents/ip");
    //	ofstream cout("/home/aditya/Documents/op");

	int t;
	cin>>t;


	while(t--)
	{
		memo=VI(SIZE,-1);

		int e,f;
		cin>>e>>f;

		int n;
		cin>>n;

		VII info(n);

		for(int i=0;i<n;i++)
		{
			cin>>info[i].F>>info[i].S;
		}




		if(f-e==0)
		 cout<<"0\n";
		else {


			int res= dp(f-e,info);


			if(res==-2)
			 cout<<"This is impossible.\n";
			else cout<<"The minimum amount of money in the piggy-bank is "<<res<<".\n";



		}

	}

}