LeetCode/cs/product-of-array-except-self.cs

public class Solution {
    private int Get(int[] products, int idx) {
        if (idx < 0 || idx >= products.Length) {
            return 1;
        }
        return products[idx];
    }

    public int[] ProductExceptSelf(int[] nums) {
        var left = new int[nums.Length];
        var right = new int[nums.Length];

        for (var i = 0; i < nums.Length; ++i) {
            left[i] = nums[i] * Get(left, i - 1);

            int j = nums.Length - i - 1;
            right[j] = nums[j] * Get(right, j + 1);
        }

        var result = new int[nums.Length];

        for (var i = 0; i < nums.Length; ++i) {
            result[i] = Get(left, i - 1) * Get(right, i + 1);
        }

        return result;
    }
}