628. Maximum-Product-of-Three-Numbers

difficulty: Easy

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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.

Method One

class Solution {
    public int maximumProduct(int[] nums) {
        int min1 = Integer.MAX_VALUE;
        int min2 = Integer.MAX_VALUE;
        int max1 = Integer.MIN_VALUE;
        int max2 = Integer.MIN_VALUE;
        int 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);
    }
}
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