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 [3,10000] 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.

Solution: find out the three largest numbers and the two smallest numbers using one pass.

    public int maximumProduct(int[] nums) {
        int max1 = Integer.MIN_VALUE, max2 = Integer.MIN_VALUE, max3 = Integer.MIN_VALUE, min1 = Integer.MAX_VALUE, min2 = Integer.MAX_VALUE;
        for (int n : nums) {
            if (n > max1) {
                max3 = max2;
                max2 = max1;
                max1 = n;
            } else if (n > max2) {
                max3 = max2;
                max2 = n;
            } else if (n > max3) {
                max3 = n;
            }

            if (n < min1) {
                min2 = min1;
                min1 = n;
            } else if (n < min2) {
                min2 = n;
            }
        }
        return Math.max(max1*max2*max3, max1*min1*min2);
    }