ProductsExceptCurrent.java

import java.util.Arrays;

class Solution {
    public int[] products(int[] nums) {
        int[] result = new int[nums.length];
        if (nums.length > 1) {
            result[0] = 1;
        }

        int productSoFar = nums[0];

        for (int i = 1; i < nums.length; i++) {
            result[i] = productSoFar;
            productSoFar = productSoFar * nums[i];
        }

        productSoFar = nums[nums.length - 1];
        for (int i = nums.length - 2; i >= 0; i--) {
            result[i] = result[i] * productSoFar;
            productSoFar = productSoFar * nums[i];
        }

        return result;
    }

    public static void main(String[] args) {
        System.out.println(Arrays.toString(new Solution().products(new int[]{1, 2, 3, 4, 5})));
        System.out.println(Arrays.toString(new Solution().products(new int[]{1})));
        System.out.println(Arrays.toString(new Solution().products(new int[]{10, 20, 0, 30, 40})));
    }
}