高精度很折磨心态…

#include <iostream>
#include <cstring>
#include <vector>
#include <utility>
#include <map>
#include <queue>
#include <algorithm>
#include <cmath>
#include <stack>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<double, double> pdd;

const int N = 1e5;

pii arr[N];

bool cmp(pii a, pii b){
    return a.first < b.first;
}
bool larger(vector<int> &a, vector<int> &b){
    int len_a = a.size(), len_b = b.size();
    if(len_a != len_b) return len_a > len_b;
    else{
        for(int i = len_a - 1; i >= 0; i--)
            if(a[i] != b[i]) return a[i] > b[i];
    }
    return false;
}

bool equal(vector<int> &a, vector<int> &b){
    int len_a = a.size(), len_b = b.size();
    if(len_a != len_b) return false;
    else{
        for(int i = len_a - 1; i >= 0; i--)
            if(a[i] != b[i]) return false;
    }
    return true;
}
vector<int> mul_Axb(vector<int> &a, int b){
    vector<int> c;
    int len_a = a.size(), carry = 0, pro;
    for(int i = 0; i < len_a; i++){
        pro = a[i] * b + carry;
        c.push_back(pro % 10);
        carry = pro / 10;
    }
    while(carry){
        c.push_back(carry % 10);
        carry /= 10;
    }
    while(c.size() > 1 && c.back() == 0) c.pop_back();
    return c;
}

// A / b = C ... r, A >= 0, b > 0
vector<int> div_A_b(vector<int> &a, int b){
    vector<int> c;
    int len_a = a.size(), dividend, r;
    for(int i = len_a - 1; i >= 0; i--){
        dividend = r * 10 + a[i];
        c.push_back(dividend / b);
        r = dividend % b;
    }
    reverse(c.begin(), c.end());
    while(c.size() > 1 && c.back() == 0) c.pop_back();
    return c;
}
// 将数字x转为逆序存储的数组
void to_vec(int x, vector<int>& c){
    if (x == 0) c.push_back(0);
    while (x > 0) {
        c.push_back(x % 10);
        x /= 10;
    }
}


int main(){
    int n, x, l ,r;
    cin >> n;
    for(int i = 0; i <= n; i++){
        cin >> l >> r;
        arr[i] = make_pair(l * r, l);
    }
    sort(arr + 1, arr + n + 1, cmp);

    vector<int> pre_mul(1);
    pre_mul = mul_Axb(pre_mul, arr[0].second);

    vector<int> res(0), ans(0);

    for(int i = 1; i <= n; i++){
        res = div_A_b(pre_mul, arr[i].first/arr[i].second);

        if(larger(res, ans)) ans = res;
        pre_mul = mul_Axb(pre_mul, arr[i].second);

    }
    for(int i = ans.size() - 1; i >= 0; i--){
        cout << ans[i];
    }
}