[C#] 判斷星期幾

星期一 ~ 星期日

var today = DateTime.Now;


if (today.DayOfWeek == DayOfWeek.Monday)

if (today.DayOfWeek == DayOfWeek.Tuesday)

if (today.DayOfWeek == DayOfWeek.Wednesday)

if (today.DayOfWeek == DayOfWeek.Thursday)

if (today.DayOfWeek == DayOfWeek.Friday)

if (today.DayOfWeek == DayOfWeek.Saturday)

if (today.DayOfWeek == DayOfWeek.Sunday)

...

[Logic] Find the unique number

題目 :
There is an array with some numbers. All numbers are equal except for one. Try to find it!

findUniq([ 1, 1, 1, 2, 1, 1 ]) === 2
findUniq([ 0, 0, 0.55, 0, 0 ]) === 0.55

-----

my ans :
 public static int GetUnique(IEnumerable<int> numbers)
  {
     var result = numbers.GroupBy(
      c => c,
      (key,g) => new { a = key, count = g.Count()})
      .Where(c => c.count == 1)
      .Select(c => c.a).Single();

     return result;
  }

[Logic] IQ Test

題目 :

Bob is preparing to pass IQ test. The most frequent task in this test is to find out which one of the given numbers differs from the others. Bob observed that one number usually differs from the others in evenness. Help Bob — to check his answers, he needs a program that among the given numbers finds one that is different in evenness, and return a position of this number.

! Keep in mind that your task is to help Bob solve a real IQ test, which means indexes of the elements start from 1 (not 0)

##Examples :

IQ.Test("2 4 7 8 10") => 3 // Third number is odd, while the rest of the numbers are even

IQ.Test("1 2 1 1") => 2 // Second number is even, while the rest of the numbers are odd


不加思索的弱code :

var list = numbers.Split(' ');
var temp = int.Parse(list[0]) % 2;
var temp2 = int.Parse(list[1]) % 2;
var count = 3;

for (int i = 2; i < list.Count(); i++)
{
var a = int.Parse(list[i])% 2;
if ( a != temp && temp == temp2 )
{
break;
}
else if ( a != temp && temp != temp2 )
{
count = 1;
break;
}
else if ( a != temp2 && temp != temp2 )
{
count = 2;
break;
}
count++;
}
return count++;

---

優雅的code :

  var nums = numbers.Split(' ').Select(n => int.Parse(n));
  var isEven = nums.Count(n => n % 2 == 0) == 1;
  return nums.Select(n => n % 2 == (isEven ? 0 : 1)).ToList().IndexOf(true) + 1;