628. Maximum Product of Three Numbers

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.

class Solution {
    public int maximumProduct(int[] nums) {
        if(nums == null || nums.length == 0) return 0;
        
        
        int min1 = Integer.MAX_VALUE, min2 = Integer.MAX_VALUE;
        int max1 = Integer.MIN_VALUE,max2 = Integer.MIN_VALUE, max3 = Integer.MIN_VALUE;
        
        for(int n : nums){
            if(n < min1){
                min2 = min1;
                min1 = n;
            }
            else if(n < min2){
                min2 = n;
            }
            
            if(n > max1){
                max3 = max2;
                max2 = max1;
                max1 = n;
            }else if(n > max2){
                max3 = max2;
                max2 = n;
            }else if(n > max3){
                max3 = n;
            }
        }
        
        return Math.max(min1*min2*max1, max1*max2*max3);
    }
}