leetcode Integer Break

Given a positive integer n, break it into the sum of at least two positive integers and maximize the product of those integers. Return the maximum product you can get.

For example, given n = 2, return 1 (2 = 1 + 1); given n = 10, return 36 (10 = 3 + 3 + 4).

Note: You may assume that n is not less than 2 and not larger than 58.

思路：尽量拆出3来，这样积会很大。

证明我写纸上咯：

导数在1-lnx =0，即x=e时取极值。2<e<3, e=2.7离3要近一点。所以选3.

int integerBreak(int n) {    if (n==2) return 1;    if (n==3) return 2;    int pro=1;    while(n>4){        pro = 3*pro;        n=n-3;    }        pro = pro*n;    return pro;}