count coins

public static int coinSum(List<int> coins, int total)
    {
        var dp = new int[total + 1];
        dp[0] = 1;

        for(int i = 0; i < coins.Count; i++)
            for(int coin = coins[i]; coin < total + 1; coin++)
                dp[coin] += dp[coin - coins[i]];

        return dp[total];
    }