50TLE求调（拒绝某p开头语言党）

#include<bits/stdc++.h>
using namespace std;
int n;
string ans;
unordered_map<string, unordered_map<string, string>> m;
string operator+(string s1, string s2){
    if(s1.size() < s2.size())
        swap(s1, s2);
    if(s2 == "0")
        return s1;
    reverse(s1.begin(), s1.end());
    reverse(s2.begin(), s2.end());
    s2.resize(s1.size(), '0');
    s1.push_back('0');
    for(size_t i = 0; i < s2.size(); ++i){
        s1[i] += s2[i] - '0';
        if(s1[i] > '9'){
            s1[i] -= 10;
            ++s1[i + 1];
        }
    }while(s1.back() == '0')
        s1.pop_back();
    if(s1.empty())
        return "0";
    reverse(s1.begin(), s1.end());
    return s1;
}string operator*(string s1, string s2){
    if(s1 == "0" or s2 == "0")
        return "0";
    if(s2 == "10"){
        s1.push_back('0');
        return s1;
    }if(m.count(s1) and m[s1].count(s2))
        return m[s1][s2];
    if(s1.size() == 1 and s2.size() == 1)
        return m[s1][s2] = to_string((s1[0] - '0') * (s2[0] - '0'));
    string ans("0");
    for(char c: s1)
        ans = ans * "10" + s2 * string(1, c);
    return m[s1][s2] = ans;
}bool cmp(string s1, string s2){
    if(s1.size() != s2.size())
        return s1.size() > s2.size();
    return s1 > s2;
}string operator-(string s1, string s2){
    if(!cmp(s2, s1)){
        reverse(s1.begin(), s1.end());
        reverse(s2.begin(), s2.end());
        s2.resize(s1.size(), '0');
        s1.push_back('0');
        for(size_t i = 0; i < s2.size(); ++i){
            int k = s2[i] - '0';
            s1[i] -= k;
            if(s1[i] < '0'){
                s1[i] += 10;
                --s1[i + 1];
            }
        }while(s1.back() == '0')
            s1.pop_back();
        if(s1.empty())
            return "0";
        reverse(s1.begin(), s1.end());
        return s1;
    }else{
        string s3 = s2 - s1;
        auto it = s3.begin();
        s3.insert(it, '-');
        return s3;
    }
}string power(string s, int k){
    string ans = "1";
    do{
        if(k & 1)
            ans = ans * s;
        s = s * s;
    }while(k >>= 1);
    return ans;
}int main(){
    scanf("%d", &n);
    ans = power("2", n) - "1";
    printf("%u", ans.size());
    reverse(ans.begin(), ans.end());
    ans.resize(500, '0');
    reverse(ans.begin(), ans.end());
    for(int i = 0; i < 500; ++i){
        if(i % 50 == 0)
            printf("\n");
        putchar(ans[i]);
    }return 0;
}