No_1051.cs

/*
A school is trying to take an annual photo of all the students. The students are asked to stand in a single file line in non-decreasing order by height. Let this ordering be represented by the integer array expected where expected[i] is the expected height of the ith student in line.

You are given an integer array heights representing the current order that the students are standing in. Each heights[i] is the height of the ith student in line (0-indexed).

Return the number of indices where heights[i] != expected[i].

 

Example 1:

Input: heights = [1,1,4,2,1,3]
Output: 3
Explanation: 
heights:  [1,1,4,2,1,3]
expected: [1,1,1,2,3,4]
Indices 2, 4, and 5 do not match.
Example 2:

Input: heights = [5,1,2,3,4]
Output: 5
Explanation:
heights:  [5,1,2,3,4]
expected: [1,2,3,4,5]
All indices do not match.
Example 3:

Input: heights = [1,2,3,4,5]
Output: 0
Explanation:
heights:  [1,2,3,4,5]
expected: [1,2,3,4,5]
All indices match.
 

Constraints:

1 <= heights.length <= 100
1 <= heights[i] <= 100
*/

using System.Linq.Expressions;

namespace LeetCode
{
    public class No_1051
    {
        public int HeightChecker(int[] heights)
        {
            int[] copy = new int[heights.Length];
            Array.Copy(heights, copy, heights.Length);
            Array.Sort(heights);
            int c = 0;

            for (int i = 0; i < heights.Length; i++)
            {
                if (heights[i] != copy[i])
                    c++;
            }
            return c;
        }

        public int HeightChecker_counter(int[] heights){
            int[] indexes = new int[101];
            int c = 0;

            for (int i = 0; i < heights.Length; i++)
             {
                indexes[heights[i]]++;
            }

            int j = 0;
            for (int i = 0; i < heights.Length; i++)
            {
                while (indexes[j] == 0)
                {
                    j++;
                }
                if (heights[i] != j)
                 c++;
                indexes[j]--;

            }

            return c;
        }
    }


}