LeetCode刷题【Array】 Maximum Product of Three Numbers

【题目】

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.

解决一： sort Array

public class Solution {    public int maximumProduct(int[] nums) {        if(nums==null) return 0;Arrays.sort(nums);int ret = nums[0]*nums[1]*nums[nums.length-1];int ret1 = nums[nums.length-1]*nums[nums.length-2]*nums[nums.length-3];return ret>ret1? ret:ret1;    }}

解决二：

public class Solution {    public int maximumProduct(int[] nums) {int [] maxs = new int[3];int [] mins = new int[3];maxs[0]=maxs[1]=maxs[2]=mins[0]=mins[1]=mins[2]=nums[0];for(int i=0; i< nums.length;i++){if(nums[i]>maxs[2]){maxs[0]=maxs[1];maxs[1]=maxs[2];maxs[2]=nums[i];}else if(nums[i]>maxs[1]){maxs[0]=maxs[1];maxs[1]=nums[i];}else if(nums[i]>maxs[0]){maxs[0]=nums[i];}if(nums[i]<mins[2]){mins[0]=mins[1];mins[1]=mins[2];mins[2]=nums[i];}else if(nums[i]<mins[1]){mins[0]=mins[1];mins[1]=nums[i];}else if(nums[i]<mins[0]){mins[0]=nums[i];}}int ret=maxs[0]*maxs[1]*maxs[2];int ret1 = mins[2]*mins[1]*maxs[2];return ret>ret1? ret:ret1;    }}

【参考】

https://leetcode.com/problems/maximum-product-of-three-numbers/#/description