int Foo(int[] arr1, int[] arr2) {
    Array.Sort(arr2);
    Dictionary<(int, int), int> memo = new Dictionary<(int, int), int>();

    int DP(int i, int prev) {
        if (i == arr1.Length) return 0;
        if (memo.ContainsKey((i, prev))) return memo[(i, prev)];

        int cost = int.MaxValue;
        if (arr1[i] > prev) {
            int nextCost = DP(i + 1, arr1[i]);
            if (nextCost != int.MaxValue) {
                cost = Math.Min(cost, nextCost);
            }
        }

        int idx = Array.BinarySearch(arr2, prev + 1);
        if (idx < 0) idx = ~idx;
        if (idx < arr2.Length) {
            int nextCost = DP(i + 1, arr2[idx]);
            if (nextCost != int.MaxValue) {
                cost = Math.Min(cost, 1 + nextCost);
            }
        }

        memo[(i, prev)] = cost;
        return cost;
    }

    int result = DP(0, int.MinValue);
    return result == int.MaxValue ? -1 : result;
}

int[] arr1 = { 0, 11, 6, 1, 4, 3 };
int[] arr2 = { 5, 4, 11, 10, 1, 0 };
int minOperations = Foo(arr1, arr2);
Console.WriteLine(minOperations);  // output: 5