628. Maximum Product of Three Numbers --E

Q:

Given an integer array, find three numbers whose product is maximum and output the maximum product.

Example 1:

Input: [1,2,3]
Output: 6

 

Example 2:

Input: [1,2,3,4]
Output: 24

 

Note:

1. The length of the given array will be in range [3,104] and all elements are in the range [-1000, 1000].
2. Multiplication of any three numbers in the input won't exceed the range of 32-bit signed integer.

 

A:

注意vector 排序的语法

class Solution {
public:
    int maximumProduct(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        int n = nums.size();
        if(nums[0]>=0 || nums[n-1]<=0)
            return nums[n-1] * nums[n-2] * nums[n-3];
        int v1 = nums[n-1] * nums[n-2] * nums[n-3];  // trhe possible Positive
        int v2 = nums[n-1] * nums[1] * nums[0];    // two negative + 1 positive
        return max(v1,v2);        
    }
};