MaxProductOfThree.java

package MaxProductOfThree;

// note: need to import (for using "Arrays.sort(int[])")
import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int[] A) {

        // main idea: 
        // max_1 = positive * positive * positive
        // max_2 = negative * negative * positive
        // max = Math.max(max_1, max_1)
        // just need to sort the integer array
        
        // sort the array
        Arrays.sort(A);

        // max_1 = 1st biggest * 2nd biggest * 3rd biggest 
        int max_1 = A[A.length-1] * A[A.length-2] * A[A.length-3];
        
        // max_2 = 1st smallest * 2nd smallest * 1st biggest
        int max_2 = A[0] * A[1] * A[A.length-1];

        // take the maximum        
        int max = Math.max(max_1, max_2);
        
        return max;
    }
}