题目大意：给出一个整数，，问吧这个整数分成任意多个正整数只和的最大乘积是多少。
思路：根据小学奥数的基本知识，我们要吧这个数字分成尽量多个3。然后这个题就解决了。
CODE：
#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>using namespace std;struct BigInt{int num[10010],len;BigInt(int _ = 0) {memset(num,0,sizeof(num));num[len = 1] = _;}BigInt operator *(int a)const {BigInt re;re.len = len;int temp = 0;for(int i = 1; i <= len; ++i) {re.num[i] = num[i] * a + temp;temp = re.num[i] / 10;re.num[i] %= 10;}while(temp)re.num[++re.len] = temp % 10,temp /= 10;return re;}};int n;int main(){cin >> n;BigInt ans(1);if(n % 3 == 0)for(int i = 1; i <= n / 3; ++i)ans = ans * 3;else if(n % 3 == 1) {for(int i = 1; i <= (n – 1) / 3 – 1; ++i)ans = ans * 3;ans = ans * 4;}else {for(int i = 1; i <= (n – 1) / 3; ++i)ans = ans * 3;ans = ans * 2;}cout << ans.len << endl;for(int i = ans.len,T = 1; T <= min(100,ans.len); ++T,–i)printf("%d",ans.num[i]);return 0;}
接受失败也等于给了自己从零开始的机会，
