问题描述:
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.
Hint:
1)There is a simple O(n) solution to this problem.
2)You may check the breaking results of n ranging from 7 to 10 to discover the regularities.
把一个非负整数n分拆成至少两个整数之和,求分拆后各数乘积的最大值。
问题求解:
class Solution {
public:
int integerBreak(int n) {
if(n < 4) return n-1;
int res = 1;
while(n > 2){//看n包含多少个3,把他们相乘,直到n<=2
res *= 3;
n -= 3;
}
if(n == 0) return res;//n可以整除3,res就是各个3相乘
if(n == 1) return (res / 3 ) * 4;//除3余1,把其中的一个3加1变为4再相乘
if(n == 2) return res * 2;//除3余2,则可直接把2与res相乘
}
};