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Height Checker - Array - Easy - LeetCode - MiniTV

Height Checker - Array - Easy - LeetCode - मिनी टीवी

Students are asked to stand in non-decreasing order of heights for an annual photo.

Return the minimum number of students that must move in order for all students to be standing in non-decreasing order of height.

Notice that when a group of students is selected they can reorder in any possible way between themselves and the non selected students remain on their seats.

 

Example 1:

Input: heights = [1,1,4,2,1,3]

Output: 3

Explanation: 

Current array : [1,1,4,2,1,3]

Target array  : [1,1,1,2,3,4]

On index 2 (0-based) we have 4 vs 1 so we have to move this student.

On index 4 (0-based) we have 1 vs 3 so we have to move this student.

On index 5 (0-based) we have 3 vs 4 so we have to move this student.

 

Example 2:

Input: heights = [5,1,2,3,4]

Output: 5

 

Example 3:

Input: heights = [1,2,3,4,5]

Output: 0

 

Constraints:

 

1 <= heights.length <= 100

1 <= heights[i] <= 100

 

Solution:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace LeetCode.AskGif.Easy.Array
{
    public class HeightCheckerSoln
    {
        public int HeightChecker(int[] heights)
        {
            var copy = new int[heights.Length];
            copy = heights;

            copy = copy.OrderBy(c => c).ToArray();

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

            return count;
        }
    }
}

 

Time Complexity: O(nlogn)

Space Complexity: O(n)

 

Unit Tests:

using LeetCode.AskGif.Easy.Array;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Collections.Generic;
using System.Text;

namespace CodingUnitTest.Easy.Array
{
    [TestClass]
    public class HeightCheckerSolnTests
    {
        [TestMethod]
        public void HeightCheckerSoln_First()
        {
            var arr = new int[] { 1, 1, 4, 2, 1, 3 };
            var expected = 3;

            var res = new HeightCheckerSoln().HeightChecker(arr);
            Assert.AreEqual(expected, res);
        }

        [TestMethod]
        public void HeightCheckerSoln_Second()
        {
            var arr = new int[] { 5, 1, 2, 3, 4 };
            var expected = 5;

            var res = new HeightCheckerSoln().HeightChecker(arr);
            Assert.AreEqual(expected, res);
        }

        [TestMethod]
        public void HeightCheckerSoln_Third()
        {
            var arr = new int[] { 1, 2, 3, 4, 5 };
            var expected = 0;

            var res = new HeightCheckerSoln().HeightChecker(arr);
            Assert.AreEqual(expected, res);
        }
    }
}