1464

public class Solution {
    public int MaxProduct(int[] nums) {
        var pq = new PriorityQueue<int, int>(nums.Select(x => (x, -x)));
 
        return (pq.Dequeue() - 1) * (pq.Dequeue() - 1);
    }
}

^With a heap

---

Actually, no need for a heap.

public class Solution {
    public int MaxProduct(int[] nums) {
         int max1 = 0, max2 = 0;   // constraints: nums[i] >= 1
 
        foreach (int x in nums) {
            if (x > max1) { max2 = max1; max1 = x; }
            else if (x > max2) max2 = x;
        }
 
        return (max1 - 1) * (max2 - 1);
    }
}