LeetCode 343 Integer Break (数学)

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.

Hint:

There is a simple O(n) solution to this problem.
You may check the breaking results of
n ranging from 7 to 10 to discover the regularities.

题目链接：https://leetcode.com/problems/integer-break/

题目分析：尽可能的分成若干3的积，除3余1则将最后的4拆成2 * 2，除3余2则直接乘2

public class Solution {
public int integerBreak(int n) {
if (n < 4) {
return n - 1;
}
int num3 = n / 3, ans = 1, mod = n % 3;
for (int i = 0; i < num3 - 1; i ++) {
ans *= 3;
}
if (mod == 1) {
ans *= 4;
}
else if (mod == 2) {
ans *= 6;
}
else {
ans *= 3;
}
return ans;
}
}