public void IsUniqueTest_ReturnFalse(string inputStr)
        {
            bool result = Question_1_1.IsUnique(inputStr);

            Assert.IsFalse(result, $"{inputStr} is unique.");

            result = Question_1_1.IsUniqueInplaceNestedLoop(inputStr);
            Assert.IsFalse(result, $"{inputStr} is unique - In-place Nested Loop.");

            result = Question_1_1.IsUniqueInplaceSort(inputStr);
            Assert.IsFalse(result, $"{inputStr} is unique - In-place Sort.");
        }
        public void IsUniqueTest_ReturnTrue(string inputStr)
        {
            bool result = Question_1_1.IsUnique(inputStr);

            Assert.IsTrue(result, $"{inputStr} contains duplicates.");

            result = Question_1_1.IsUniqueInplaceNestedLoop(inputStr);
            Assert.IsTrue(result, $"{inputStr} contains duplicates - In-place Nested Loop.");

            result = Question_1_1.IsUniqueInplaceSort(inputStr);
            Assert.IsTrue(result, $"{inputStr} contains duplicates - In-place Sort.");
        }