題目:
https://onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=15&page=show_problem&problem=1264
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| #include <iostream> #include <vector> #include <string> #include <algorithm>
using namespace std;
void multiply(vector<int> &v, int n){ if(v.size() > 11) return; 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; }
string factorial(int n){ if(n == 0) return "1";
vector<int> v = {1};
for(int i=2; i<=n; ++i){ multiply(v, i); }
string result = "";
for(int i=0; i<v.size(); ++i){ result += to_string(v[i]); }
reverse(result.begin(), result.end());
return result; }
int main(){ string str; int n; while(cin >> n){ str = factorial(n); if(str.size() >= 11) cout << "Overflow!\n"; else if(str.size() < 5) cout << "Underflow!\n"; else cout << str << '\n'; } return 0; }
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