public void Test1()
{
int[] nums = new int[] { 1, 2, 3, 3, 3 };
Solution solution = new Solution(nums);
// pick(3) should return either index 2, 3, or 4 randomly. Each index should have equal probability of returning.
var four = solution.Pick(3);
// pick(1) should return 0. Since in the array only nums[0] is equal to 1.
var one = solution.Pick(1);
Assert.AreEqual(one, 0);
}