Codility Lesson 3-1 Time Complexity

TapeEquilibrium.cs

using System;
using System.Linq;
// you can also use other imports, for example:
// using System.Collections.Generic;

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

class Solution {
    public int solution(int[] A) {
        var totalSum = A.ToList().Sum();
		var minDif = int.MaxValue;

		var prevSum = 0;

		for (int i = 0; i < A.Length-1; i++)
		{
			prevSum += A[i];
			var rest = totalSum - prevSum;
			var dif = Math.Abs(prevSum - rest);
			minDif = dif < minDif ? dif : minDif;
		}
			
		return minDif;
        
        // write your code in C# 6.0 with .NET 4.5 (Mono)
    }
}