dp

#include 
      
       #include 
       
        #include 
        
         #include 
         
          using namespace std;#define MAX_COIN_NUM 505#define MAX_CAP 10005struct Coin{    int price, weight;}coin[MAX_COIN_NUM];int capacity;int coin_num;int f[MAX_CAP]; void input(){    int a, b;    scanf("%d%d", &a, &b);    capacity = b - a;    scanf("%d", &coin_num);    for (int i = 0; i < coin_num; i++)        scanf("%d%d", &coin[i].price, &coin[i].weight);}void work(){    memset(f, -1, sizeof(f));    f[0] = 0;    for (int i = 0; i < coin_num; i++)        for (int j = coin[i].weight; j <= capacity; j++)            if (f[j - coin[i].weight] != -1)            {                int temp = f[j - coin[i].weight] + coin[i].price;                if (f[j] == -1 || f[j] > temp)                    f[j] = temp;            }}int main(){    int t;    scanf("%d", &t);    while (t--)    {        input();        work();        if (f[capacity] == -1)            printf("This is impossible.\n");        else            printf("The minimum amount of money in the piggy-bank is %d.\n", f[capacity]);    }    return 0;}