Uva10280-old wine into new bottles

#include<cstdlib>#include<iostream>#include<cstdio>#include<cmath>#include<set>#include<cstring>#include <algorithm>#define inf 0x7fffffff#define N 450000#define MIN 1e-11#define M 100#define LL long longusing namespace std;int n,k,h,t,m;int a[N],b[N],low[M],high[M];int main(){#ifndef ONLINE_JUDGE    freopen("ex.in","r",stdin);#endif    scanf("%d",&t);    while(t--)    {        memset(a,0,sizeof(a));        memset(b,0,sizeof(b));        int v,minv=inf,temp;        scanf("%d%d",&v,&n);        v*=1000;        for(int i=0; i<n; ++i)        {            scanf("%d%d",&low[i],&high[i]);            temp=low[i]*low[i]/(high[i]-low[i]);            if(minv>temp)                minv=temp;        }        if(v>minv)        {            printf("0\n");            if(t)                printf("\n");            continue;        }        a[0]=1;        for(int i=0; i<n; i++)            for(int j=low[i]; j<=v; j++)            {                if(a[j-low[i]])                {                    a[j]=1;                    b[j]=max(b[j],b[j-low[i]]+high[i]);                }            }        int maxv=0;        for(int i=v; i>=0; i--)            if(b[i]>maxv)            {                maxv=b[i];                if(maxv>=v)                {                    maxv=v;                    break;                }            }        printf("%d\n",v-maxv);        if(t)            printf("\n");    }    return 0;}