public void BackspaceCompareTest()
{
var s = new Solution();
Assert.True(s.BackspaceCompare("ab#c", "ad#c")); // true, "ac"
Assert.True(s.BackspaceCompare("ab##", "c#d#")); // true, ""
Assert.True(s.BackspaceCompare("a##c", "#a#c")); // true, "c"
Assert.False(s.BackspaceCompare("a#c", "b")); // false, "c" > "b"
}