/*

tomorrow practice this:

https://javarevisited.blogspot.com/2015/07/how-to-find-duplicate-words-in-string-java.html

1. reverseWordsString() = reverse words in a given string - method 1

2. reverseWordsFromString(String str) - reverse words in a given string - method 2

3. Charactorcount(String str) - count the occurrence of each character in a string - method 1

4. countcharsinString(String str) - count the occurrence of each character in a string - using Linq -method 2 

5. countcharsDictionary(String str) - 1) Count the occurrence of each character in a string using Dictionary- method 3

                                      2) Find the duplicate characters in a given word ex: Java a => 2

6. ReverseString(String str) - using different way: method3

7. reverseString(String str) - Reverse a given string - method1

8. reverseStringUsingSB(String text) - using Stringbuilder: method2

9. reverseStringUsingReverse(String str) - Reverse a given string using to Array - method4

10 DuplicateWordsInString(String str) - find duplicate words in a given string using expressions - method1

11. FindRepeatedWords(String str) - find duplicate words in a given string using Collections - method2

12. sortwords() - Sorting words using linq or array sort method.

13. sortStringAsc(String str) - Sort a string array in ascending order

14. ReversewordsinArray() - reverse a given String arrary 

15. ReverseCharArray()reverse a char arrary

16. FindDuplicates() - Find Duplicates in String Arrary

17. FindPalindrome(String str) - 

18. removeduplicatesfromString() - remove duplicate charactors from a given string ex:  java => jav

19. charOccursInString(String str) - count number of occurrence of any character on String:

20.getMaxOccuringChar(String str) - maximum occurance of charector in a string

​

https://www.java67.com/2018/04/21-string-programming-and-coding-interview-questions-answers.html

​

*/

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

​

public class Program

{

​

    public static void Main()

    {

        //FindDuplicates();

        //ReverseCharArray();

        removeduplicatesfromString();

    }

​

    //1. Reverse a word

    public static void reverseWordsString(string str){

        //String fromreverse = "cheppu na kodaka";

        string toreverse = "";

        for (int i = str.Length -1 ; i > -1 ; i --){

            toreverse += str.ElementAt(i);

            // toreverse  = toreverse + str.ElementAt(i);

        }

        Console.WriteLine(toreverse);

    }

    //2.reverse words in a given string - method 2

    internal static void reverseWordsFromString(String str){

​

        String[] splitString = str.Split(' ');

        int temp;

        int k  = splitString.Length - 1;

        temp = k;

        for (int i= k; i >= 0; i--){

            Console.Write(splitString[temp]+ "" + ' ');

            --temp;

        }   

​

​

    }

    //3.count the occurrence of each character in a string - method 1

​

    public static void Charactorcount(String str){

        str = str.Replace(" ", "");

        while (str.Length >0){

            Console.Write(str[0] + " : ");

            int count = 0;

            for (int i = 0; i< str.Length; i++){

                    if (str[0] == str[i] && str[0] != ' ')

                    {

                        count++;

                    }

​

            }

            Console.WriteLine(count);

            str = str.Replace(str[0].ToString(), String.Empty);

        }

    }

    //4. count the occurrence of each character in a string - method 2

    public static void countcharsinString(String str){

        var charLookup = str.Where(char.IsLetterOrDigit).ToLookup(c => c); // IsLetterOrDigit to exclude the space

​

            foreach (var c in charLookup)

        Console.WriteLine("Char:{0} Count:{1}", c.Key, charLookup[c.Key].Count());

    }

    //5. Count the occurrence of each character in a string using Dictionary- method 3

    //Find the duplicate characters in a given word ex: Java a => 2

    public static void countcharsDictionary(String str){

        Dictionary<char,int> dict = new Dictionary<char,int>();

        foreach (char c in str.Replace(" ", String.Empty)){

            if (dict.ContainsKey(c)){

                dict[c] = dict[c] + 1;

            }

            else

                dict.Add(c,1);

        }

        foreach (var cr in dict.Keys){

            if (dict[cr] > 1)

            Console.WriteLine(cr + ":" + dict[cr]);

        }

    }

​

​

    //6.. Reverse a given string - method1

    public static void reverseString(String str){

        char[] chr = str.ToCharArray();

            for (int i=0, j = str.Length-1; i<j; i++,j--){

                chr[i] = str[j];

                chr[j] = str[i];

            }

            String reveredString = new String(chr);

            Console.WriteLine(reveredString);

    }

    //7. using Stringbuilder: method2

    public static void reverseStringUsingSB(String text){

        if (String.IsNullOrEmpty(text)){

            Console.WriteLine("enter a valid string: ");

        }

            StringBuilder builder = new StringBuilder(text.Length);

        for(int i = text.Length - 1; i>=0; i--){

                builder.Append(text[i]);

            }

        Console.WriteLine(builder.ToString());

    }

​

    //8.using different way: method3

    public static void ReverseString(String str){

        String r = "";

        for (int i = str.Length-1; i>-1; i--){

            r += str[i];

        }

        if (r.Equals(str)){

        Console.WriteLine("word is Palindrome");

        }

        else 

        Console.WriteLine("not");

    }

    //9. Reverse a given string using to Array - method4

    public static void reverseStringUsingReverse(String str){

        char[] chr = str.ToCharArray();

        Array.Reverse(chr);

        String reversedString = new String(chr);

        Console.WriteLine(reversedString);

    }   

    //10. find duplicate words in a given string using expressions - method1

    public static void DuplicateWordsInString(String str){

            int count =0;

        str  = str.ToLower();

​

        String[] s = str.Split(' ');

        Console.WriteLine("repeated words in a given string: " + str);

        for (int i = 0 ; i<s.Length ; i++){

            count = 1;

                for (int j= i+1; j<s.Length; j++){

                    if (s[i].Equals(s[j])){

                        count++;

                    s[j] = "0";

                    }

                }

            if (count > 1 && s[i] != null)

​

                    Console.WriteLine( s[i] + " : " + count);

            }

    }

​

    //11. find duplicate words in a given string using Collections - method2

    // find words count in a given string

    public static void FindRepeatedWords(String str){

        //split a string 

        var value = str.Split();

        //create a dictionary to hold the count

        Dictionary<String, int> repeatedwordsct = new Dictionary<String, int> ();

        Console.WriteLine("repeated words in a given string: " );

        //

        for (int i = 0 ; i < value.Length; i++){

            if (repeatedwordsct.ContainsKey(value[i])){

                int count = repeatedwordsct[value[i]];

                repeatedwordsct[value[i]] = count+1;

            }

            else 

            {

                repeatedwordsct.Add(value[i],1);

            }

        }

        foreach (KeyValuePair<String, int> kvp in repeatedwordsct){

            if (kvp.Value > 1)

            Console.WriteLine(kvp.Key + ":" + kvp.Value);

        }

    }

    public static void FindLengthofWord(String s){

        //char[] chr = s.ToCharArray();

        Console.Write( s.Length);

​

    }

    // 12. Sorting words using linq

    public static void sortwords(){

        String[] stringarray = {"banana", "grapes", "orange", "mango"};

        //using arrary sort method: Array.Sort(stringarray);

        //using linq 

        var result = from name in stringarray

                     orderby name

                     select name;

        foreach (String s in result){

            Console.WriteLine(s);

        }

    }

    //13. Sort a string in ascending order

    public static void sortStringAsc(String str){

        char ch;

        char[] arr1 = str.ToCharArray();

        for (int i=1 ; i < str.Length ; i++){

            for (int j = 0 ; j < str.Length - i ; j++){

                if (arr1[j] < arr1[j+1]){

                    ch = arr1[j];

                    arr1[j] = arr1[j+1];

                    arr1[j+1] = ch;

                }

            }   

        }

        foreach (char c in arr1)

            Console.WriteLine(c);

    }

​

    //14. reverse a string arrary

    public static void ReversewordsinArray(){

        String [] Names = {"Krishna", "Siri", "Snig", "Adhi", "tour"};

        Console.WriteLine("Words before Reverse: {0} ", String.Join(",", Names));

        for(int i= 0 ; i < Names.Length /2 ; i++){

            string temp = Names[i];

            Names[i] = Names[Names.Length-1-i];

            Names[Names.Length-1-i] = temp;

        }

        Console.Write("Reversed String: ");

        Console.WriteLine(String.Join(",",Names));

        /*foreach (String word in Names){

         Console.WriteLine(word);

        }*/

    }

    //15. reverse a char arrary

    public static void ReverseCharArray(){

        Char [] letters = {'v', 'S','d','a'};

        Console.WriteLine("chars before Reverse: {0} ", String.Join(",", letters));

        for(int i= 0 ; i < letters.Length /2 ; i++){

            char ch = letters[i];

            letters[i] = letters[letters.Length-1-i];

            letters[letters.Length-1-i] = ch;

        }

        Console.Write("Reversed chars: ");

        Console.WriteLine(String.Join(",",letters));

        /*foreach (String word in Names){

         Console.WriteLine(word);

        }*/

    }

    //16. Find Duplicates in String Arrary

    public static void FindDuplicates(){

           string [] array = new string[]{"Ram", "Sam", "Ram", "Sita", "Ram", "Sam"};

           Array.Sort(array);

            for (int i = 0; i < array.Length; i++)

            {

                int count = 1,k=-1;

                for (int j = i+1; j < array.Length; j++)

                {  

​

                        if(array[i] == array[j])

                        {

                            count++;

                            k=j-1;

                        }

                        else break;

                }

                if (count > 1)

                Console.WriteLine("\t\n " + array[i] + "--->" + count);            

                if(k!=-1)

                    i=k+1;          

            }

    }

        //https://stackoverflow.com/questions/9790749/check-if-a-string-is-a-palindrome

    //17. Word is Palindrome or not

    public static void FindPalindrome(String str){

        String r = "";

        str = str.ToLower();

        for (int i = str.Length-1; i>-1; i--){

            r += str[i];

        }

        if (r.Equals(str)){

        Console.WriteLine("word is Palindrome");

        }

        else 

        Console.WriteLine("not");

    }

    //18. remove duplicate charactors from a given string

    public static void removeduplicatesfromString(){

        String name = "java rava";

        Console.WriteLine("Before removing duplicate chars: {0} ", name);

        HashSet<char> hs = new HashSet<char>(name);

         name = new string(hs.ToArray()); 

        Console.WriteLine("After removing duplicate chars: {0} ", name);

​

    }

    //19. count number of occurrence of any character on String:

    public static void charOccursInString(String str){

        int count = 0;

        for (int i = 0 ; i < str.Length ; i ++){

            if (str.ElementAt(i) == 'a')

                count ++;

        }

        Console.WriteLine("count of occurrence of character 'a' on String: " + count);

​

    }

        //20. maximum occurance of charector in a string

    public static void getMaxOccuringChar(String str) 

    { 

        // Create array to keep the count of 

        // individual characters and  

        // initialize the array as 0 

        int [] count =  new int[256]; 

        // Construct character count array 

        // from the input string. 

        int len = str.Length; 

        for (int i = 0; i < len; i++) 

            count[str[i]]++; 

        int max = -1; // Initialize max count 

        char result = ' '; // Initialize result 

        // Traversing through the string and  

        // maintaining the count of each character 

        for (int i = 0; i < len; i++) { 

            if (max < count[str[i]]) { 

                max = count[str[i]]; 

                result = str[i]; 

            } 

        } 

        Console.WriteLine("Max occurring character is : " + 

                            result + "=" + max);

    }

}