[LeetCode] Problem 628 - Maximum Product of Three Numbers

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

Example

No.1

Input: [1,2,3]

Output: 6

No.2

Input: [1,2,3,4]

Output: 24

Note

  1. The length of the given array will be in range [3,10^4] 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.

Code

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public int maximumProduct(int[] nums) {
    int max1 = Integer.MIN_VALUE;
    int max2 = Integer.MIN_VALUE;
    int max3 = Integer.MIN_VALUE;
    int min1 = Integer.MAX_VALUE;
    int min2 = Integer.MAX_VALUE;

    for (int num : nums) {
        if (num > max1) {
            max3 = max2;
            max2 = max1;
            max1 = num;
        }
        else if (num > max2) {
            max3 = max2;
            max2 = num;
        }
        else if (num > max3) 
            max3 = num;
        
        if (num < min1) {
            min2 = min1;
            min1 = num;
        }
        else if (num < min2)
            min2 = num;
    }

    return Math.max(min1 * min2 * max1, max1 * max2 * max3);
}