LeetCode——Maximum Product of Three Numbers

Question

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:

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

Solution

排序，要么最大的三个正数乘积最大，要么是两个最小的负数和最大的正数乘积最大。

Code

class Solution {
public:
    int maximumProduct(vector<int>& nums) {
        sort(nums.begin(), nums.end(), comp);
        return max(nums[0] * nums[1] * nums[2], nums[0] * nums[nums.size() - 1] * nums[nums.size() - 2]);
    }
    static bool comp(int& a, int& b) {
        return a > b;
    }

};