Notes

using System;
using System.Collections.Immutable;
using System.Diagnostics.Contracts;
using System.Security.Cryptography.X509Certificates;

namespace AlgoPractice;

class Program
{
public static void Main(string[] args)
{
MergeArray();
//DescOrder();
//string rev = "";

//for(int i = str.Length-1;i>=0; i--)
//{
// rev += str[i] ;
//}
//Console.WriteLine(rev);
}
//Merge two sorted array
public static void MergeArray()
{
int[] arr1 = new int[10];
int[] arr2 = new int[10];
Console.WriteLine("First array");
for (int i = 0; i < 10; i++)
{
arr1[i] = Convert.ToInt32(Console.ReadLine());
}
Console.WriteLine("Second array");
for (int i = 0; i < 10; i++)
{
arr2[i] = Convert.ToInt32(Console.ReadLine());
}
Console.WriteLine("Merge array");
int[] arr3 = new int[20];
Array.Sort(arr1);
Array.Sort(arr2);
int n = 10;
int m = 10;
while (n > 0)
{
arr3[n-1] = arr1[n-1];
n--;
}
while (m > 0)
{
arr3[m+n-1] = arr2[m+n-1];
m--;
}
for(int i=0;i<arr3.Length;i++)
{
Console.WriteLine(arr3[i]);
}
}

//Majority element in an array
public static void MajorityElement()
{
int[] arr = { 1, 2, 3, 3, 4, 6, 7, 7, 7,7,8, 8 };
int[] maj = new int[arr.Length];
for(int i=0;i<arr.Length;i++)
{
maj[arr[i]]++;
}
int max = 0;
for(int i = 0; i < arr.Length; i++)
{
if (max < maj[arr[i]])
{
max = arr[i];
}
}
Console.WriteLine(max);
}
//sort an array in descending order
public static void DescOrder()
{
int[] arr = { 1, 25, 3, 4, 58, 63, 76, };

for(int i=0;i<arr.Length;i++)
{
for (int j = i; j < arr.Length; j++)
{
if (arr[i] < arr[j])
{
int temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
}
}
Console.WriteLine("Sorted array is:");
for (int i = 0; i < arr.Length; i++)
{
Console.WriteLine(arr[i]);
}
Console.WriteLine("Reversed array is:");
Array.Reverse(arr);
for (int i = 0; i < arr.Length; i++)
{
Console.WriteLine(arr[i]);
}

}
//two array sum results into target
public static bool TwoSum()
{
int[] arr = { 1, 2, 3, 4, 5, 6 };
int target = 7;
for(int i=0;i<arr.Length;i++)
{
for(int j = i+1; j < arr.Length; j++)
{
if (arr[i] + arr[j] == target)
{
return true;
}
}
}
return false;
}
//all substrings in a string
public static string Sub(string s)
{
string subs = "";
for(int i=0;i<s.Length;i++)
{
for(int j = 0; j < s.Length - i; j++)
{
subs = subs + " " + s.Substring(i,j);
}
}
return subs;
}
//replace all spaces with %20
public static string ReplaceSpace(string s)
{
string res = s.Replace(" ", "%20");
return res;
}
//all unique characters
public static bool uniqueChar(string s)
{

int[] arr= new int[10000];
for(int i=0;i<s.Length;i++)
{
arr[s[i]]++;
}
for(int i=0;i< s.Length;i++)
{
if (arr[s[i]] != 1)
{
return false;
}
}
return true;
}

//Highest occurring character
public static char HighOccurence(string str)
{

int[] maxCount = new int[2000];
int count = 0;
char rev = ' ';
for (int i = 0; i < str.Length; i++)
{
maxCount[str[i]]++;
}
for (int i = 0; i < str.Length; i++)
{
if (count < maxCount[str[i]])
{
count = maxCount[str[i]];
rev = str[i];
}
}
return rev;
}
//Duplicate characters
public static string RemoveDuplicate(string s)
{
if (s == null)
{
Console.WriteLine("string is empty");
}
string res = new string(s.Distinct().ToArray());
return res;

}
//string Palindrome
public static bool Palindrome(string str)
{
bool result = false;

for(int i=0;i<str.Length-1;i++)
{
if (str[i] == str[(str.Length-1) - i])
{
result = true;
}
}
return result;

}
//count words in a string
public static int CountString(string str)
{
int count = 0;
str = str.Trim();
if(str == "")
{
return 0;
}
while(str.Contains(" "))
{
str.Replace(" ", " ");
}
foreach(string s in str.Split(' '))
{
count++;
}
return count;
}
//reverse recursion
public static string Reverse(string str)
{
if (str.Length == 1)
{
return str;
}

return str.Last()+Reverse(str.Substring(0,str.Length-1));
}
}