Abbreviate Product | O(B−A) | 100% Optimized C#
IntuitionThe product grows too large for direct computation, so we track only the leading and trailing digits while counting trailing zeros.Approach
Leading dig
# Intuition
The product grows too large for direct computation, so we track only the leading and trailing digits while counting trailing zeros.

# Approach
1. Leading digits (value): Multiply and normalize to keep only the first few significant digits while counting shifts (digitShift).
2. Trailing digits (remainder): Multiply, remove trailing zeros (countZeros), and keep only the last 14 digits to avoid overflow.
3. Result construction:
    - If the product has ≤10 significant digits, return it normally.
    - Otherwise, return "prefix...suffixeC" format.

# Complexity
- Time complexity:
O(B−A), since we iterate through the range once.

- Space complexity:
O(1), using only a few variables.

# Code
```csharp []
public class Solution {
    public string AbbreviateProduct(int a, int b) {
        double value = 1.0;
        int countZeros = 0, digitShift = 0;
        long remainder = 1;
        
        for (int num = a; num <= b; num++) {
            value *= num;
            while (value >= 1) 
            {
                value /= 10;
                digitShift++;
            }

            remainder *= num;
            while (remainder % 10 == 0) 
            {
                countZeros++;
                remainder /= 10;
            }

            if (remainder > (long)Math.Pow(10, 14))
                remainder %= (long)Math.Pow(10, 14);
        }

        if (digitShift - countZeros <= 10) 
            return ((long)(value * Math.Pow(10, digitShift - countZeros) + 0.5)).ToString() + "e" + countZeros;
        else 
        {
            string prefix = ((long)(value * 100000)).ToString();
            string suffix = (remainder % 100000).ToString().PadLeft(5, '0');
            return prefix + "..." + suffix + "e" + countZeros;
        }
    }
}

```

# Explanation
1. Initialize value, remainder, digitShift, and countZeros.
2. Loop through [a, b], updating value and remainder, counting shifts and trailing zeros.
3. Format the result based on digit length.
['Math', 'C#']