vijos 1779 国王游戏

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxn 1050
using namespace std;
struct pnt
{
    int x,y;
}p[maxn];
int n,a,b;
struct bign
{
    int len,a[4050];
};
bign base,ans;
bool cmp(pnt x,pnt y)
{
    return max(y.y,x.y*x.x)<max(x.y,y.x*y.y);
}
void reset()
{
    ans.len=0;ans.a[0]=0;
    int ret=a;base.len=0;
    while (ret)
    {
        base.a[base.len]=ret%10;
        ret/=10;base.len++;
    }
    base.len--;
}
bign operator / (bign x,int m)
{
    int ret[4050],len=0,data=0;
    for (int i=x.len;i>=0;i--)
    {
        data=data*10+x.a[i];
        ret[++len]=data/m;data%=m;
    }
    int now=1;while ((!ret[now]) && (now<=len)) now++;
    bign y;
    if (now==len+1)
    {
        y.len=0;y.a[0]=0;
        return y;
    }
    y.len=len-now;
    for (int i=y.len;i>=0;i--)
    {
        y.a[i]=ret[now];
        now++;
    }
    return y;
}
bool operator > (bign x,bign y)
{
    if (x.len<y.len) return false;
    if (x.len>y.len) return true;
    int top=x.len;
    for (int i=top;i>=0;i--)
    {
        if (x.a[i]>y.a[i]) return true;
        if (x.a[i]<y.a[i]) return false;
    }
}
bign operator * (bign x,int m)
{
    bign y,ans;
    while (m) {y.a[y.len++]=m%10;m/=10;}
    y.len--;
    for (int i=0;i<=x.len+y.len+1;i++) ans.a[i]=0; 
    for (int i=0;i<=x.len;i++)
        for (int j=0;j<=y.len;j++)
            ans.a[i+j]+=x.a[i]*y.a[j];
    for (int i=0;i<=x.len+y.len;i++)
    {
        ans.a[i+1]+=ans.a[i]/10;
        ans.a[i]%=10;
    }
    ans.len=x.len+y.len;
    if (ans.a[x.len+y.len+1]) ans.len++;
    return ans;
}
int main()
{
    scanf("%d",&n);
    scanf("%d%d",&a,&b);
    for (int i=1;i<=n;i++) scanf("%d%d",&p[i].x,&p[i].y);
    sort(p+1,p+n+1,cmp);
    reset();
    for (int i=1;i<=n;i++)
    {
        bign ret=base/p[i].y;
        if (ret>ans) ans=ret;
        base=base*p[i].x;
    }
    for (int i=ans.len;i>=0;i--) printf("%d",ans.a[i]);
    return 0;
}