題目:
https://onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=14&page=show_problem&problem=1161
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| #include <iostream>
#include <vector>
#include <string>
using namespace std;
void multiply(vector<int> &v, int n){
int carry = 0;
for(int i=0; i<v.size(); ++i){
int product = v[i] * n + carry;
v[i] = product % 10;
carry = product / 10;
}
while(carry > 0){
v.push_back(carry % 10);
carry /= 10;
}
return;
}
int factorial_sum(int n){
if(n == 0) return 1;
vector<int> v = {1};
for(int i=2; i<=n; ++i){
multiply(v, i);
}
int sum = 0;
for(int i=0; i<v.size(); ++i){
sum += v[i];
}
return sum;
}
int main(){
int n, ans;
while(cin >> n){
ans = factorial_sum(n);
cout << ans << '\n';
}
return 0;
}
|
