无高精度已60，写了坑坑巴巴的高精度目前只过1,2， 求助各位大佬

#include<bits/stdc++.h>
using namespace std;
const int M = 4010;
struct eee {
	int l;
	int r;
} a[10005];
int n, l1, r1; //初始左右手
int num[M], ans[M], tmp[M] = {1}, ttmp[M]; //左手乘积，答案，临时数组

bool is(eee x, eee y)
{
	return x.l * x.r < y.l * y.r;
}
void P_multiplication(int p[M], int y) //高乘单
{
	//乘
	for (int i = M - 1; i >= 0; i--) p[i] *= y;
	for (int i = 0; i < M; i++) {
		//进位
		p[i + 1] += (p[i] / 10);
		p[i] %= 10;
	}

}
void Pcopy(int p[M],int v[M])
{
	for (int i = M - 1; i >= 0; i--) v[i] = p[i];
}
void P_division(int p[M], int b[M], int y) //高除单
{
	for (int i = M - 1; i >= 0; i--) {
		if (p[i] < y) {
			p[i - 1] += 10 * p[i];
			p[i] = 0;
			b[i] = 0;
		} else {
			b[i] = p[i] / y;
			p[i - 1] += 10 * (p[i] % 10);
		}
	}
}


bool compare(int v[M], int b[M]) //比较
{
	for (int i = M ; i >= 0; i--) {
		if (v[i] > b[i]) {
			return 1;
			break;
		} //1:v比b大 2:v比b小
		if (v[i] < b[i]) {
			return 0;
			break;
		}
		
	}
	return 0;
}

void pcout(int v[M])//输出
{
	bool eep = 0;
	for (int i = M-1 ; i >= 0; i--) {
			if (v[i]) {
				eep = 1;
			}
			if (eep == 1) cout << v[i];
		}
}
int main()
{

	cin >> n >> l1 >> r1;
	for (int i = 1; i <= n; i++) cin >> a[i].l >> a[i].r;
	sort(a + 1, a + 1 + n, is);
	/*for (int i = 1; i <= n; i++) cout<< a[i].l << a[i].r;
	return 0;*/
	//对l1做预处理
	P_multiplication(tmp, l1);
	for (int i = 1; i <= n; i++) {
		int tttmp[M];
		
		Pcopy(tmp,tttmp);
		P_division(tmp, ttmp, a[i].r);
		Pcopy(tttmp,tmp);
		P_multiplication(tmp, a[i].l);
		if (compare(ttmp, ans)) Pcopy(ttmp, ans);
		memset(ttmp, 0, sizeof(ttmp));
	}
	pcout(ans);
	return 0;
}